Chas Freeman, in The New York Times writes:

The last war with Iraq greatly enhanced American prestige and influence. The irony is that this war with Iraq, intended by its proponents to consolidate United States hegemony, may erode and undermine it. Even if things go well, it could yield weakened American alliances and influence, a more anemic presence overseas, a diminished capacity to project power, fewer options and allies in the Middle East, and an increased threat of terrorism. From here, it looks like a bad bet against long odds.