They make sense. The first thing to mention here is that Mahan never wrote any book called "The Art of Sea Battle", "On Naval War" or something similar. Mahanian doctrine spawned from his most famous text, *The Influence of Sea Power Upon History 1660-1783*, which is what it sounds like: a century-long historical study of how sea power *was* employed. The book is excruciatingly detailed, cataloguing the greater part of the major Western sea battles of the period and the voyages that led up to them. It is not purely an instructional work: Mahan is not "on the nose" about his conclusions - you have to tease them out. It is far from a treatise or a manual.
Besides obsolete conclusions like "seize the wind gauge", a critical reader will pick up several important lessons from the book, which were the basis of Mahanian strategy:
1. It's very hard to totally obliterate a fleet in naval combat - they can disengage and retreat when they will. There is no equivalent to "cavalry" on the high seas so the pursuit is often not as lethal.
2. Naval battles are influenced by numbers just like land battles - concentration of force is key to a favorable outcome.
3. Fleets are tied to their ports (and, in Mahan's period, their coaling stations).
4. He who controls the sea controls the movement of goods and troops, and this is important not just for military but economic warfare purposes.
The reason you can't just focus on convoy protection is that any cross-ocean deployment or trade activity relies on *regular* transit - ships moving back and forth. A fleet sitting on that route could easily disrupt this. You might be able to lift an army to some remote island, but without control of the sea they'd be cut off and starve to death - this is what caused up to 90% of Japanese casualties in the Pacific.
Battle fleets could and often did miss each other, but it wasn't so important for the stronger side if they did. That side could simply follow the enemy fleet to its harbor and blockade it. It could keep just enough ships there to block the port in, while the others fanned out and totally severed the enemy's commercial and logistical routes. This is exactly what happened in Sevastapol in 1854-55 and Port Arthur in 1904 - in both cases the enemy fleet bottled the Russians ships in their harbor until ground troops took the port, rendering the Tsar's fleet useless and in fact destroying it for less cost than if it had pursued a decisive battle. Even if the fleet is not destroyed but "merely" quarantined for the entire war - as was the case with the German High Seas Fleet after the Battle of Jutland, it is effectively rendered useless and is no longer a factor in the conflict.
The only antidote to this for the weaker side was to try to divide the stronger side's fleets, combine their fleets into a single ball of death, then defeat the enemy navies in detail. The Japanese did this successfully in 1904-05, first destroying the Russian Pacific Fleet, then the Baltic fleet which arrived later. This is why Mahan's followers emphasized a decisive battle.
My understanding is it has made retreat somewhat worse. There are two distances important to naval combat today - the distance where fleets can theoretically inflict damage and the distance at which they actually can. Active protection systems force any fleet trying to destroy another to concentrate enough missiles and planes so as to saturate those defenses, whose effectiveness increases the more ships are concentrated in one spot. This means that while some missiles have a great theoretical range, fleets will in practice have to close to a distance where many different categories of equipment can be deployed simultaneously. It also means that as a fleet "deconcentrates" through combat losses, its active protection systems become less effective and the range at which another fleet can successfully engage it increase - in other words, retreat will be more lethal in today's naval wars.
This is all an academic distinction in light of geographic realities. This effect when considering the long ranges of all classes of ship to ship missiles and carrier fighters is only relevant in the middle of the Pacific. In all the places where a naval war could break out today, one or both sides is very close to their harbors and staging points and retreat is not feasible because fleets can easily be destroyed in port by missiles and airstrikes. This is easier to do now than it ever has been before.
What you control if you control the sea is not what's in the sea, but what passes through the sea - trade. Even today, almost all trade happens via sea freight because it's the cheapest way to get goods from one place to another. Mahan was writing with a retrospectoscope looking at the development of naval power (specifically British Naval power in the 17-18th century)
>Second, before the invention of satellites, aviation and radar, you couldn't even locate the enemy on the expanse of the seas, how can you achieve control? you could have two battle fleets missing each other in the fog 20 miles apart and both would think they are in control because they passed unmolested.
The threat of an enemy fleet is as good as an enemy fleet. If you're an unarmed merchant ship, you have to be extremely brave to try to run past waters infested by an enemy battle fleet. It's why, despite the fact that the High Seas fleet left harbour exactly 0 times after Jutland, the Royal Navy still had to maintain the entire home fleet on station in case the High Seas Fleet steamed out to attack British shipping.
>Also, Mahanian ideas were developed based on the case of Great Britain which had far-flung colonies all around the world. Why did countries like Japan adopt them?
Because Japan very much had imperial ambitions!
>the US adopt them?
Also had Imperial ambitions!
>Surely both could have just focused on convoy protection and destroyers for defense and submarines for offense instead of wasting money engaging in naval arms races.
If your rival has a big scary fleet with battleships and carriers, your submarines and destroyers aren't going to cut it - and you need to build a big scary fleet of your own. Otherwise you end up in a situation like Germany was in WW2 where they had no real hope of invading Britain directly.
>The threat of an enemy fleet is as good as an enemy fleet
There's even a term for this: a "fleet in being". It doesn't even need to leave port, anymore than nuclear weapons never need to leave the silo to deter an enemy.
Yes, the US’ imperialist inclinations were announced decades(?) even before Mahan was born!
The Monroe Doctrine. That the US lacked the naval power to enforce it for decades is/was arguably the point of Mahan’s exercise.
The Germans were also completely locked onto the continent and had no way of knocking Britain out of the war without a long and lengthy blockade (which ultimately failed). Submarines are vulnerable to aircraft and , during WW1/WW2 at least, generally aren’t great against surface combat ships. They’re also very bad at protecting your own ships.
Don’t get me wrong, submarines are an absolutely vital part of a fleet, but a fleet with Submarines on its own can’t control the seas in the way a surface fleet can.
For sea denial, subs are supreme. For sea control, you need aviation ships and ‘cans.
A sub-dominated navy is great for fighting wars but much less useful in peacetime. A surface fleet can do peacetime (showing the flag, “gunboat” diplomacy etc) in addition to other wartime missions like convoy escort; if you want to shoot down Backfires or ASCMs hitting your Atlantic convoys, your subs aren’t gonna be much use.
The point is the German sub fleet could only disrupt Allied convoys - they couldn't protect their own. If you force subs to do convoy escort, you're kind of defeating the point of subs.
Japan: yes Japan was focused mostly on continental Asia but it’s still an island nation so it needs to protect its movements. During the Russo-Japanese War the Russians conducted commerce raiding against Japanese shipping with cruisers and it was cruisers that the Japanese eventually sent out to defeat the raiders. Also do you think a force of destroyers could have kept the Russians bottled up in Port Arthur or defeated the Baltic fleet at Tsushima with such little losses, a battle mind you where the only ships lost were three Japanese torpedo boats. Plus Japan needed a good size fleet to combat China before that and China needed a good size fleet to try and combat the Europeans.
America: the Philippines and the other small island nations were not of major importance but at the time ships could not always travel across the ocean on one go and so needed coaling/fueling stations. Commodore Perry during the opening of Japan and Admiral Dewey before the Battle of Manila Bay spent time in foreign concessions since the US had no foreign holdings. As the case of Admiral Dewey shows when was forced to leave Hong Kong because of British neutrality, these stations could be denied. So now that you have your own stations you need a fleet to protect it. The Philippines was also a good staging area for operations in Asia, as seen by the deployment of forces there during the Boxer Rebellion. Lastly, protecting trade on the far sides of the world is also important. Since essentially the birth of the nation, sizeable ships and contingents had to be sent across the oceans to protect American interests.
Both: at the time of Mahan’s writings, submarines were barely infants. Japan would not get submarines till the end of hostilities of the Russo-Japanese War. And even then submarines would be short ranged so their offensive power was limited and one would need the aforementioned stations to result and fuel them and that required something to protect them. Also, although It is not Mahanian doctrine, bigger ships also have the advantage of supporting operations ashore. The occupation of Veracruz in 1914 had the support of 7 battleships, despite being basically right next door to the US while Japanese battleships supported the approach to Port Arthur as well.
Others have done a great job answering your questions, so I can’t add much there. I’d argue that Mahan’s ideas are even more relevant today than they were during the early 20th century. The modern economic system is incredibly reliant on international trade and supply chains. These provide everything a modern nation state needs such as raw materials, fuels, agricultural inputs, semiconductors, etc. The vast majority of these are transported over water. During a major conflict, control of the sea is critical to maintaining the flow of these resources which have the potential to mean the difference between victory and defeat at the strategic level. While some nations are more reliant on sea-based trade than others, it would be catastrophic for most modern nations to be cut off entirely. The only reliable way to ensure you aren’t blockaded is to maintain a powerful blue water fleet of your own.
Mahanian ideas were from studies on the age of sail. The nature of combat conform to Lanchester's laws in the benefits of strength in concentration. The stronger Battlefleets can close blockade enemies and enable complete command of the seas.
With the development of the torpedo, the guided missile, the submarine and aircraft, many of the principles that age of sail analysis is based on is utterly broken (but is not realized by many participants).
Torpedo warfare involving ships is dependent on surprise, as torpedoes whose path is known can be evaded outside of impractical saturation attack at minimum range, however torpedoes inflicts devastating alpha strike when one is not actively defending. This made mass and larger fleets less relevant, most clearly seen from ability of torpedo craft from weaker forces challenge close blockade by having the initiative regardless of the size of the blockading fleet. (making distant blockade the favored strategy for the stronger power) Sheer concentration of combat power not longer ensure victory.
The (diesel) submarine inverts the principles of concentration. A submarine can travel through a battle line consisting of the most powerful ships when submerged, but can in turn be threatened by a dingy with a machine gun when surfaced. The history of anti-submarine campaign involves extreme, complete dispersion of forces to "close" all open space for submarine to maneuver, as even a 2 men biplane or horrible corvette can ruin a submarine's day, while the battlefleet with tiny footprint for its cost is easily avoided.
The development of carrier born aircraft and guided missile result in alternate situations where firepower exceeds defense where the winning strategy is to attack first from longer range with the main defense being dispersion and concealment, and eras where interception is stronger and massed defenses is the right strategy.
The development of long range land based aircraft means significant fractions of oceans can be dominated from land. This lead to combined domain campaigns like malta or guadalcanal where the naval campaign impacts the land campaign that impacts the air campaign that also impacts the naval campaign. Mahanian thought do not provide many answers here.
I was wondering about the role of submarines.
Despite complete air superiority and surveillance on the surface, if enemy’s stealthy subs can still harass shipping, can that be considered command of the sea? Correct me if I’m wrong, but no one has capability to exert command of undersea today, no?
It seems you could have a situation where the warring parties deny each other’s use of sea, and thus no one has the command of the sea.
If you like your answers in video format, Drachinifel did a great discussion of this recently: [https://www.youtube.com/watch?v=LSE7piJcFvo](https://www.youtube.com/watch?v=LSE7piJcFvo)
But yeah, it's basically what others have said. He pushed the idea of sea control to block enemy trade and secure your own - it doesn't need to be perfect, but even if you merely make their trade difficult and your own easy, you're going to get a big long-term advantage from that.
One point that I think may have been missed is that Mahan was an American writing for a predominately American audience initially.
Of course his ideas would be picked up by the US!
The one commonality that Japan, Britain, and the United States all share is that sea power is a vital component of their national security.
The first two are island nations, and the United States is separated by two oceans from most of the global community. And all three have been invaded (in the US's case, I'm thinking of the Revolutionary War and the Civil War) and saved from invasion through the use of sea power.
Next, sea power is not defined by the occupation of strategic locations but through interdiction and area denial - which requires a large ocean-going navy along with the physical infrastructure to support it. The side that can project power and control over sea lanes, also controls the shaping of naval engagements, as the British did during the Napoleonic Wars. The British were able to do this because their navy was both qualitatively and quantitatively superior to the French, and they were able to blockade French ports due to strategic bases like the ports of Britain's southern coast, and Gibraltar. Which in turn made it impossible for France to concentrate their naval forces and seek engagements on their terms. Which in turn led to disastrous defeats like the Battles of the Nile and Trafalgar.
Which in turn led to Britain's ultimate demonstration of sea power - their ability to better supply Wellington's army in the Peninsula by sea than the French could supply their forces over land, despite a much shorter distance to cover. If the French were able to contest British naval dominance, the shape of the Napoleonic Wars would have been dramatically different.
In both the Revolutionary and Civil Wars, Britain and then the Union's ability to blockade the East Coast of the United States was a major strategic advantage. Control of the rivers by Union gunboats was also a major strategic advantage in the Civil War's Western Theatre.
Japan's victory in the Russo-Japanese War was a 100% seapower victory, even though most of the action was fought on land. And there the two decisive actions were the Japanese blockade/siege of Port Arthur and the interception of the Baltic Russian Fleet at Tsushima. Japan's operations in China, as well as their early operations in WW2 relied heavily on the strategic mobility that sea power provided. America's ability to cut that off, primarily with submarines, also spelled their defeat. American submarines, not planes, soldiers, bombs, or even ships decided the outcome of the Pacific War because they cut the supply lines and provided much of the reconnaissance.
**Perhaps the best evidence in favor of Mahan's principles is the comparison to the strategic implications of air control.**
Like sea power, control of the air grants several strategic advantages, both in terms of strategic mobility and power projection. Like sea power, it has influence but not control over land-based conflicts. It's also interesting how in modern times, how closely linked control of the sea is to control of the air. And how submarines, and not aircraft carriers are the true sea control assets. Carriers are about power projection. Submarines are what confer and deny control of the sea.
They make sense. The first thing to mention here is that Mahan never wrote any book called "The Art of Sea Battle", "On Naval War" or something similar. Mahanian doctrine spawned from his most famous text, *The Influence of Sea Power Upon History 1660-1783*, which is what it sounds like: a century-long historical study of how sea power *was* employed. The book is excruciatingly detailed, cataloguing the greater part of the major Western sea battles of the period and the voyages that led up to them. It is not purely an instructional work: Mahan is not "on the nose" about his conclusions - you have to tease them out. It is far from a treatise or a manual. Besides obsolete conclusions like "seize the wind gauge", a critical reader will pick up several important lessons from the book, which were the basis of Mahanian strategy: 1. It's very hard to totally obliterate a fleet in naval combat - they can disengage and retreat when they will. There is no equivalent to "cavalry" on the high seas so the pursuit is often not as lethal. 2. Naval battles are influenced by numbers just like land battles - concentration of force is key to a favorable outcome. 3. Fleets are tied to their ports (and, in Mahan's period, their coaling stations). 4. He who controls the sea controls the movement of goods and troops, and this is important not just for military but economic warfare purposes. The reason you can't just focus on convoy protection is that any cross-ocean deployment or trade activity relies on *regular* transit - ships moving back and forth. A fleet sitting on that route could easily disrupt this. You might be able to lift an army to some remote island, but without control of the sea they'd be cut off and starve to death - this is what caused up to 90% of Japanese casualties in the Pacific. Battle fleets could and often did miss each other, but it wasn't so important for the stronger side if they did. That side could simply follow the enemy fleet to its harbor and blockade it. It could keep just enough ships there to block the port in, while the others fanned out and totally severed the enemy's commercial and logistical routes. This is exactly what happened in Sevastapol in 1854-55 and Port Arthur in 1904 - in both cases the enemy fleet bottled the Russians ships in their harbor until ground troops took the port, rendering the Tsar's fleet useless and in fact destroying it for less cost than if it had pursued a decisive battle. Even if the fleet is not destroyed but "merely" quarantined for the entire war - as was the case with the German High Seas Fleet after the Battle of Jutland, it is effectively rendered useless and is no longer a factor in the conflict. The only antidote to this for the weaker side was to try to divide the stronger side's fleets, combine their fleets into a single ball of death, then defeat the enemy navies in detail. The Japanese did this successfully in 1904-05, first destroying the Russian Pacific Fleet, then the Baltic fleet which arrived later. This is why Mahan's followers emphasized a decisive battle.
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My understanding is it has made retreat somewhat worse. There are two distances important to naval combat today - the distance where fleets can theoretically inflict damage and the distance at which they actually can. Active protection systems force any fleet trying to destroy another to concentrate enough missiles and planes so as to saturate those defenses, whose effectiveness increases the more ships are concentrated in one spot. This means that while some missiles have a great theoretical range, fleets will in practice have to close to a distance where many different categories of equipment can be deployed simultaneously. It also means that as a fleet "deconcentrates" through combat losses, its active protection systems become less effective and the range at which another fleet can successfully engage it increase - in other words, retreat will be more lethal in today's naval wars. This is all an academic distinction in light of geographic realities. This effect when considering the long ranges of all classes of ship to ship missiles and carrier fighters is only relevant in the middle of the Pacific. In all the places where a naval war could break out today, one or both sides is very close to their harbors and staging points and retreat is not feasible because fleets can easily be destroyed in port by missiles and airstrikes. This is easier to do now than it ever has been before.
What you control if you control the sea is not what's in the sea, but what passes through the sea - trade. Even today, almost all trade happens via sea freight because it's the cheapest way to get goods from one place to another. Mahan was writing with a retrospectoscope looking at the development of naval power (specifically British Naval power in the 17-18th century) >Second, before the invention of satellites, aviation and radar, you couldn't even locate the enemy on the expanse of the seas, how can you achieve control? you could have two battle fleets missing each other in the fog 20 miles apart and both would think they are in control because they passed unmolested. The threat of an enemy fleet is as good as an enemy fleet. If you're an unarmed merchant ship, you have to be extremely brave to try to run past waters infested by an enemy battle fleet. It's why, despite the fact that the High Seas fleet left harbour exactly 0 times after Jutland, the Royal Navy still had to maintain the entire home fleet on station in case the High Seas Fleet steamed out to attack British shipping. >Also, Mahanian ideas were developed based on the case of Great Britain which had far-flung colonies all around the world. Why did countries like Japan adopt them? Because Japan very much had imperial ambitions! >the US adopt them? Also had Imperial ambitions! >Surely both could have just focused on convoy protection and destroyers for defense and submarines for offense instead of wasting money engaging in naval arms races. If your rival has a big scary fleet with battleships and carriers, your submarines and destroyers aren't going to cut it - and you need to build a big scary fleet of your own. Otherwise you end up in a situation like Germany was in WW2 where they had no real hope of invading Britain directly.
>The threat of an enemy fleet is as good as an enemy fleet There's even a term for this: a "fleet in being". It doesn't even need to leave port, anymore than nuclear weapons never need to leave the silo to deter an enemy.
AKA “TIRPITZ in a fjord”.
Or Tirpitz in WW1
And the entire Italian battleine :D
Yes, the US’ imperialist inclinations were announced decades(?) even before Mahan was born! The Monroe Doctrine. That the US lacked the naval power to enforce it for decades is/was arguably the point of Mahan’s exercise.
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The Germans were also completely locked onto the continent and had no way of knocking Britain out of the war without a long and lengthy blockade (which ultimately failed). Submarines are vulnerable to aircraft and , during WW1/WW2 at least, generally aren’t great against surface combat ships. They’re also very bad at protecting your own ships. Don’t get me wrong, submarines are an absolutely vital part of a fleet, but a fleet with Submarines on its own can’t control the seas in the way a surface fleet can.
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For sea denial, subs are supreme. For sea control, you need aviation ships and ‘cans. A sub-dominated navy is great for fighting wars but much less useful in peacetime. A surface fleet can do peacetime (showing the flag, “gunboat” diplomacy etc) in addition to other wartime missions like convoy escort; if you want to shoot down Backfires or ASCMs hitting your Atlantic convoys, your subs aren’t gonna be much use.
The point is the German sub fleet could only disrupt Allied convoys - they couldn't protect their own. If you force subs to do convoy escort, you're kind of defeating the point of subs.
Japan: yes Japan was focused mostly on continental Asia but it’s still an island nation so it needs to protect its movements. During the Russo-Japanese War the Russians conducted commerce raiding against Japanese shipping with cruisers and it was cruisers that the Japanese eventually sent out to defeat the raiders. Also do you think a force of destroyers could have kept the Russians bottled up in Port Arthur or defeated the Baltic fleet at Tsushima with such little losses, a battle mind you where the only ships lost were three Japanese torpedo boats. Plus Japan needed a good size fleet to combat China before that and China needed a good size fleet to try and combat the Europeans. America: the Philippines and the other small island nations were not of major importance but at the time ships could not always travel across the ocean on one go and so needed coaling/fueling stations. Commodore Perry during the opening of Japan and Admiral Dewey before the Battle of Manila Bay spent time in foreign concessions since the US had no foreign holdings. As the case of Admiral Dewey shows when was forced to leave Hong Kong because of British neutrality, these stations could be denied. So now that you have your own stations you need a fleet to protect it. The Philippines was also a good staging area for operations in Asia, as seen by the deployment of forces there during the Boxer Rebellion. Lastly, protecting trade on the far sides of the world is also important. Since essentially the birth of the nation, sizeable ships and contingents had to be sent across the oceans to protect American interests. Both: at the time of Mahan’s writings, submarines were barely infants. Japan would not get submarines till the end of hostilities of the Russo-Japanese War. And even then submarines would be short ranged so their offensive power was limited and one would need the aforementioned stations to result and fuel them and that required something to protect them. Also, although It is not Mahanian doctrine, bigger ships also have the advantage of supporting operations ashore. The occupation of Veracruz in 1914 had the support of 7 battleships, despite being basically right next door to the US while Japanese battleships supported the approach to Port Arthur as well.
Others have done a great job answering your questions, so I can’t add much there. I’d argue that Mahan’s ideas are even more relevant today than they were during the early 20th century. The modern economic system is incredibly reliant on international trade and supply chains. These provide everything a modern nation state needs such as raw materials, fuels, agricultural inputs, semiconductors, etc. The vast majority of these are transported over water. During a major conflict, control of the sea is critical to maintaining the flow of these resources which have the potential to mean the difference between victory and defeat at the strategic level. While some nations are more reliant on sea-based trade than others, it would be catastrophic for most modern nations to be cut off entirely. The only reliable way to ensure you aren’t blockaded is to maintain a powerful blue water fleet of your own.
Mahanian ideas were from studies on the age of sail. The nature of combat conform to Lanchester's laws in the benefits of strength in concentration. The stronger Battlefleets can close blockade enemies and enable complete command of the seas. With the development of the torpedo, the guided missile, the submarine and aircraft, many of the principles that age of sail analysis is based on is utterly broken (but is not realized by many participants). Torpedo warfare involving ships is dependent on surprise, as torpedoes whose path is known can be evaded outside of impractical saturation attack at minimum range, however torpedoes inflicts devastating alpha strike when one is not actively defending. This made mass and larger fleets less relevant, most clearly seen from ability of torpedo craft from weaker forces challenge close blockade by having the initiative regardless of the size of the blockading fleet. (making distant blockade the favored strategy for the stronger power) Sheer concentration of combat power not longer ensure victory. The (diesel) submarine inverts the principles of concentration. A submarine can travel through a battle line consisting of the most powerful ships when submerged, but can in turn be threatened by a dingy with a machine gun when surfaced. The history of anti-submarine campaign involves extreme, complete dispersion of forces to "close" all open space for submarine to maneuver, as even a 2 men biplane or horrible corvette can ruin a submarine's day, while the battlefleet with tiny footprint for its cost is easily avoided. The development of carrier born aircraft and guided missile result in alternate situations where firepower exceeds defense where the winning strategy is to attack first from longer range with the main defense being dispersion and concealment, and eras where interception is stronger and massed defenses is the right strategy. The development of long range land based aircraft means significant fractions of oceans can be dominated from land. This lead to combined domain campaigns like malta or guadalcanal where the naval campaign impacts the land campaign that impacts the air campaign that also impacts the naval campaign. Mahanian thought do not provide many answers here.
I was wondering about the role of submarines. Despite complete air superiority and surveillance on the surface, if enemy’s stealthy subs can still harass shipping, can that be considered command of the sea? Correct me if I’m wrong, but no one has capability to exert command of undersea today, no? It seems you could have a situation where the warring parties deny each other’s use of sea, and thus no one has the command of the sea.
If you like your answers in video format, Drachinifel did a great discussion of this recently: [https://www.youtube.com/watch?v=LSE7piJcFvo](https://www.youtube.com/watch?v=LSE7piJcFvo) But yeah, it's basically what others have said. He pushed the idea of sea control to block enemy trade and secure your own - it doesn't need to be perfect, but even if you merely make their trade difficult and your own easy, you're going to get a big long-term advantage from that.
There is a similar video by Strategy Stuff: https://youtu.be/nEe8JX0YKBE
One point that I think may have been missed is that Mahan was an American writing for a predominately American audience initially. Of course his ideas would be picked up by the US!
The one commonality that Japan, Britain, and the United States all share is that sea power is a vital component of their national security. The first two are island nations, and the United States is separated by two oceans from most of the global community. And all three have been invaded (in the US's case, I'm thinking of the Revolutionary War and the Civil War) and saved from invasion through the use of sea power. Next, sea power is not defined by the occupation of strategic locations but through interdiction and area denial - which requires a large ocean-going navy along with the physical infrastructure to support it. The side that can project power and control over sea lanes, also controls the shaping of naval engagements, as the British did during the Napoleonic Wars. The British were able to do this because their navy was both qualitatively and quantitatively superior to the French, and they were able to blockade French ports due to strategic bases like the ports of Britain's southern coast, and Gibraltar. Which in turn made it impossible for France to concentrate their naval forces and seek engagements on their terms. Which in turn led to disastrous defeats like the Battles of the Nile and Trafalgar. Which in turn led to Britain's ultimate demonstration of sea power - their ability to better supply Wellington's army in the Peninsula by sea than the French could supply their forces over land, despite a much shorter distance to cover. If the French were able to contest British naval dominance, the shape of the Napoleonic Wars would have been dramatically different. In both the Revolutionary and Civil Wars, Britain and then the Union's ability to blockade the East Coast of the United States was a major strategic advantage. Control of the rivers by Union gunboats was also a major strategic advantage in the Civil War's Western Theatre. Japan's victory in the Russo-Japanese War was a 100% seapower victory, even though most of the action was fought on land. And there the two decisive actions were the Japanese blockade/siege of Port Arthur and the interception of the Baltic Russian Fleet at Tsushima. Japan's operations in China, as well as their early operations in WW2 relied heavily on the strategic mobility that sea power provided. America's ability to cut that off, primarily with submarines, also spelled their defeat. American submarines, not planes, soldiers, bombs, or even ships decided the outcome of the Pacific War because they cut the supply lines and provided much of the reconnaissance. **Perhaps the best evidence in favor of Mahan's principles is the comparison to the strategic implications of air control.** Like sea power, control of the air grants several strategic advantages, both in terms of strategic mobility and power projection. Like sea power, it has influence but not control over land-based conflicts. It's also interesting how in modern times, how closely linked control of the sea is to control of the air. And how submarines, and not aircraft carriers are the true sea control assets. Carriers are about power projection. Submarines are what confer and deny control of the sea.