There's a new article out in the Christian Science Monitor out on military assistance and its uncertain record. The gist of it is that assistance can have public relations blowback if regimes use US-trained militaries against their own people, strategic blowback if regimes (as they frequently do) use militaries in ways that contradict US national interests, and generally does not advance U.S. interests. To some degree, they are fair criticisms. Merely spending time in the US and being schooled in an American military system is not a guarantee that an officer will be sympathetic to US strategy or act in a manner that might undermine his home country's own national interests.
However, the article ignores several salient points about military assistance. First, there is something to be said about basic interopability issues. Turkey, an example cited as a failure of military assistance, is a member of NATO. It makes sense to familiarize Turkish officers with American military, political, and cultural mores in order to better cooperate with them on issues of mutual importance. Second, military assistance and training is often one small part of larger diplomatic package and cannot be viewed in isolation. Its political benefits or demerits must be judged within the totality of the larger relationship. While seemingly insignificant on its own, it may be more useful as a part of a larger patchwork of ties. Finally, assistance, if properly and narrowly targeted toward certain areas of policy, may have beneficial effects on larger US interests.
Indeed, the issue simply seems to be a matter of realistic expectations. No amount of time in Fort Leavenworth would convince the Turks to open their territory to a military operation they thought would severely undermine their national security. We are also perfectly aware of what Pakistan considers its primary interests to be and should not be surprised if they redirect our assistance to developing their forces towards fighting India. But just because we expected more than what we should have does not mean that assistance cannot be a useful tool when it is properly aligned with a fruitful policy objective.