Congress as America's biggest problem

I disagree strongly with Timothy Garton Ash on this:

The biggest problem for American foreign policy today is not called Obama, or Bush, or China; it is called Congress. Whether you look at trade, climate change, China or Iran, it is the US Congress where policy becomes entangled, distorted and stymied. If the United States really wants to meet the hopes of a world in which its own relative power is undoubtedly diminished, it should introduce four-year terms for members of the House of Representatives, reform political finance and curb the lobbyists who enjoy "power without responsibility: the prerogative of the harlot throughout the ages". Effective foreign policy begins at home.

Ash is letting Obama off the hook by ignoring the fact that Congress doesn't set the foreign policy agenda and is not an unified enough force to take control of foreign policy away from the POTUS. One of the issues comes from the fact that almost all American presidents including Obama comes to the White House with no real experience with foreign policy or of the world (and not the world is not comprised of Kenya and Indonesia). They have  trouble adjusting to the fact that the world is not an enlarged and is complicated. For these reasons, it is difficult for them to develop quickly a real and pragmatic foreign policy's vision without listening to the same hacks that have been advising presidents for years.