The folks at Stratfor have provided a very excellent analysis of why one never fights a land war in Asia, as Robert Gates (current Secretary of Defense) stated so colorfully . Four times in the last century the United States has gotten involved in a land war in Asia, and none of them turned out gloriously–Korea, Vietnam, Afghanistan, and Iraq. What are some of the common elements to the problems the United States faced? Let us examine a few of these problems one by one.
Logistics And Demographics
Logistics and demographics are the physical components of a military force and its relative position to its food supply and the potential enemy population. In general, the further you are from your base and the more troops you need for an operation the more resources are required to feed and equip your military. Additionally, the larger the enemy population is relative to the size of your forces, the greater the “sea” for the enemy “fish” to hide in, and the harder it is to identify your enemy and protect your native allies. Additionally, the larger the space you are fighting in relative to the size of your army the less control you have over the countryside as a whole. These problems are compounded when the territory over which you are fighting is nearly worthless anyway and nearly entirely lacking in infrastructure or productive food agriculture (see Afghanistan).
There really aren’t a whole lot of useful solutions to these problems. The use of technology (like drones, tanks, or helicopters) increases the cost as well as the number of support troops relative to combat troops, meaning fewer boots on the ground and less control of the population. The natural solutions in such a situation are either to focus on garrisoning cities and abandoning the countryside to the enemy, engaging in a never-ending series of raids and counter-raids over territory that is not going to be held anyway, seeking to train local troops of dubious loyalty to bolster one’s numbers place some of the burden of defense on the ally regime, or to exchange one’s treasure for soldiers and hire mercenaries (or “contractors”). None of these solutions is without serious difficulties, and all four of America’s Asian land wars have seen at least some of these solutions tried with varying (but generally negative) results.
Additionally, these problems of logistics and demographics lead into and help exacerbate another serious problem, that of mission creep. There are two types of wars that the United States excels at: wars where there is a conventional enemy who can be identified and killed with as much firepower as is human possible or wars that can be handled with a very small permanent force. This “Janus face” of America’s military ways of war  divides warfare into either conventional Western European fighting or Indian wars. So long as a war fits one of those two models, we can handle the high intensity but (relatively) brief conflict of wars like World Wars I and II or the Spanish-American War, or the low intensity of a conflict like the Sioux War or Philippine War. In all of these cases, either the war was aggressive–defeat enemy army x or fleet y, ensure a favorable peace settlement, bring the boys home, or was fought against an enemy whose strength was not threatening to the interests of the United States and could therefore be handled without expending too much blood and treasure.
In both of those types of wars, moreover, there is a clear mission–either this is a “major war” with the need for substantial popular support and a clear mission–free Cuba from Spanish misrule, defeat the Kaiser and make the world safe for democracy, or defeat Hitler and avenge Pearl Harbor that people could rally around, or an understanding that the conflict is a dirty little colonial war with little hope of a decisive result but at the same time little risk to the people back home (like the US occupation of Nicaragua or the Dominican Republic during the 1910’s and 1920’s). Where the mission is unclear (Afghanistan, Iraq), overly defensive (Korea), or just plain nonexistent (Vietnam), the progress of wars has been much less successful. At best, there is a stalemate (Korea).
Diplomatic And Domestic Complications
The twin problems of the physical limitations and strategic failures lead into a third problem, that of the diplomatic and domestic complications that result from wars that are apparently failing or are too expensive in blood and treasure. Let us examine each of these problems separately, understanding that all of the problems discussed in this note are interrelated.
First, the use of force has diplomatic implications. A decision to engage in a given military operation (like our simultaneous involvement in Iraq and Afghanistan) limits our resources to engage in other potential areas of conflict (like South Korea, Libya, Iran, or Somalia). Each military option presents an opportunity cost that limits our available options in other crises. In a similar fashion, if we seek to increase our potential resources of troops and supplies by increasing our number of allies or our use of diplomacy we sacrifice our ability to dictate terms and protect our own interests according to our own specifications. Every gain is counterbalanced by some kind of loss somewhere else. The problem is one of constrained optimization, in other words, constrained by physical resources, tactical and strategic abilities, as well as diplomatic considerations. None of these limitations are trivial.
There are additional complications given the nature of the United States as a democracy that is substantially leery about expensive and open-ended foreign commitments. As the American citizens are fairly quick to turn against foreign wars that are expensive in blood and treasure (see Korea, Vietnam, Iraq, and Afghanistan) without a clear threat to the direct interests and well-being of the United States, civilian and military strategists face a very serious need to identify vital interests at stake and conduct warfare in such a way that it will not drag on indefinitely. Decisive victory, clear aims and exit targets, and clearly defined enemy militaries along with adroit diplomatic moves are the hallmarks of successful American military efforts (like the Spanish-American war or Mexican-American War). None of these have been the hallmarks of American involvement in Asian land wars with the notable exception of the Pacific War in World War II, which was more of a sea war than a land war.
In conclusion, we wholeheartedly endorse Secretary Gates’ claim that “any future defense secretary who advises the president to again send a big American land army into Asia or into the Middle East or Africa should have his head examined.” Given the problems of logistics and demographics, such conflicts present difficulties (if not impossibilities) for the United States to provide sufficient force to produce decisive victory. Given the muddy or nonexistent strategic focus, what resources the United States does possess in these conflicts is often shamefully wasted on stalemates or, worse, wasted in debacles like Vietnam. Additionally, the complications such involvements provide to diplomatic aims and domestic politics often far outweigh the limited to nonexistent gains the United States has made from such conflicts. In short, Asian land wars are bad all the way around. Any sane and reasonable person should recognize that fact.
 The subject of one of my papers at Norwich University, available upon request and part of the Time Well Wasted project.