Coming off of Gunslinger's look at "old tanker syndrome," I'd like to make several points about the COIN vs. COINtra fracas.
To sum up my argument, there is a lack of historical precedent for the stereotype of an Army that suffers from making a direct choice to drink chai instead of driving tanks. There is a problem of causation in pinning COIN as the major reason an Army fails, for historical, technical, and political reasons. And if we are really afraid of losing conventionally, the fact that there has been little thought about conventional wars of the future that takes into account conventional warfare since 1945 is rather troubling.
First, it is hard to think of any militaries who suffered conventionally from being too COIN-focused. What about the British and French in World War I, you might ask? Well, of all of the flaws of both armies prior to 1914, a single-minded focus on irregular warfighting was not one of them. It is difficult to think of any major works of military history offhand that make the argument that imperial warfighting led to their problems. Rigidity, bad operational doctrine, training, poor strategy, etc, you can all make those critiques with varying degrees of accuracy. But even though those nations had colonial possessions to police and conquer, they never lost track of Europe's centrality as the prime political and military center of gravity.
The Israelis in 2006? Another oversimplification, for two reasons. First, the fact that Tel Aviv focused so much time and energy on irregular warfare stemmed from the not-too-insignificant problem of an Palestinian terrorist movement that killed 1,000 Israelis (approx 42,000 as a portion of America's population). Israeli irregular warfare focus was not a result of officers itching to quote Lawrence, sip chai, and pay CERP money--they did so to defend their population against terrorists and insurgents whose idea of a fair fight was to blow up Sbarro outlets. Second, there was also the complicating factor of new doctrines that had not been received very well and an RMA-inspired ground structure and a muddled strategy. Lastly, as I've commented before, the Israelis did not do as badly as popularly observed and Hezbollah's position was more precarious than believed.
The United States in World War I had some difficulty moving from punitive expeditions and Indian warfare to large-unit positional operations, especially because of an outdated prewar doctrine that neglected combined arms. But it is difficult to characterize the American Expeditionary Force (AEF) as a complete failure, especially as it adapted (like every other WWI major army) to the conditions of industrial warfare by the end of the conflict. The AEF experience also piggybacked into the doctrinal revisions of the next twenty years. Moreover, the political context of American history in the 19th century is not one that was conducive to creating a European-style army that could compete on the Continent. American performance even in conventional wars (The Mexican War and the Civil War) was nothing Europeans found particularly inspiring---which is why few European military observers (save the Russian Army which liked the Civil War cavalry raids) paid too much attention to American campaigns.
The fact that the Israeli, Imperial British and French, and pre-war American armed forces focused on irregular warfare at all was because irregular forces threatened national security interests---whether it was basic population security (America and Israeli) from the depredations of irregulars or the colonial control (Britain and France) in a time when colonies were pawns in a massive great game. Armed forces exist to do what politicians tell them. In neither the British and French cases were colonial service a major factor in their military difficulties. In the American and Israeli cases, one can make more of a plausible argument---but in doing so would have to take an ahistorical view of the respective political contexts. Moreover, American and Israeli difficulties did not stem in an overriding fashion from love of COIN--especially since modern COIN doctrine as practiced by the US Army did not exist in 1914 and was not something that the Israelis followed in 2006.
So to sum it up, the idea that US capabilities are dying and that it will be difficult to upshift into major combat operations because of COIN does not really have any readily identifiable historical precursors--in large part because the current situation is exceptional and because the rhetoric this fear stems from is overly simplistic. There is, of course, the perennial problem of leaders not giving the armed forces the money or attention they need, growing complacent, or just being plain unprepared (Korea, WWI, Kasserine Pass, etc), but that's another argument entirely.
The technical details of this debate have been discussed over and over. But the debate does not take into account the fact that the US, in some ways, has not fought a competent conventional adversary since Korea. Iraq barely counted during the first Gulf War and essentially self-destructed in the second. So it is natural that in peacetime or simply in an violent era in which necessary data is difficult to draw from that crucial skills might lag. As Gulliver pointed out in the linked Ink Spots post, without a compelling threat it's also difficult to gin up the resources for major 1980s-style training as well.
We have heard a lot about the threat of conventional operations. But the shape of those conventional operations in future warfare matters a lot to how we prepare for them. If future warfare is Chinese submarines playing Catch-A-Carrier in the Pacific, ground doctrine does not matter. Moreover, the next conventional war will be far different from the last three major wars the United States has fought (WWII, Korea, and the Gulf War) and look more like the conventional wars in the Third World (Yom Kippur, Iran-Iraq, Pakistani-Indian Wars, China's incursion in Vietnam, etc). For all of the hysteria about the US losing a conventional war, we are not seeing a great depth of thought about what kind of conventional war we will fight.
It seems that older concepts of conventional warfare predominate in public debate. The idea that the corps is the decisive unit, for example, was already outdated by the Gulf War, in which heavy divisions became operational building blocks in their own right. So by now everyone, even the most fervent chai-drinkers, have accepted that we will fight conventional wars in the future. What are they going to look like? What skills do we need for then? What conventional ideas from Air-Land Battle and the 1990s-early 2000s FM 100-5s do we need to change? Sven Ortmann, as usual, is one of the few who is using his deep knowledge of military history and his eye for future warfare to think about this, with an interesting blog on the "age of movement to contact."
Let's get away from the back and forth about COIN and COINtras and have a conversation about conventional operations. One, however, that must be grounded by post-World War II (non-Fulda Gap) conventional military history and a realistic projection of future adversaries and the tasks that armed forces will likely be ordered to complete in the post-COIN era.