The point is you have to ask why capital starts wars. Yes, of course there are economic reasons for war, and an economic analysis of war is valuable. But Lenin was not an idiot. He understood that war is first and foremost a politically relevant act. He did not hesitate to quote Clausewitz on this matter, nor to use him to beat Kautsky and Plekhanov over the head.
What the bourgeoisie gains from war is the opportunity of economic hegemony. What their chosen servants gain from war is the opportunity of political hegemony. It's hope not too hard to grasp how the two interests intertwine. Indeed, a strong empire does create peace…from the perspective of the empire.
Anti-imperialists does not solve this because they fall into the same trap as the neocons, mainly that their existence depends on the existence of the opposite (empire). There is a reason why the best and brightest communists were never mere anti-capitalists, anti-fascists, anti-imperialists, etc. They understood that something which is purely negative creates nothing, and that the goal of their movement is everything - to abolish the conditions by which imperialism, among other things, might continue to exist, by overcoming capitalism.
The demand that mere anti-imperialism makes is impossible to fulfill, another trap it shares with the neocons. You can never get rid of empire through anti-imperialism alone. Yet, this trap is how anti-imperialism can maintain its existence. It is therefore ideologically valuable. Likewise the empire makes impossible demands of its subjects that can never be fulfilled. The neocons will never be able to achieve total security or hegemony, their thirst can never be sated, and their existence depends on such.
Ultimately, the blunders that the American empire made in their impossible quest should be unsurprising. The American bourgeoisie and its servants have forgotten how to rule, and as time passes they become more incompentent and governed by delusions. At least the bourgeoisie in the past could be be somewhat useful and sweep away the old world! Now they are little more than degenerates, depraved and utterly void of vision.
The Reagan revolution was successful because it was crafted to specifically to destroy the international left, but now that the left is dead, they are totally lost. The glorified gang warfare mistakenly called "politics" in the American empire is a perfect representation of such. This truly is the end of history, as far as liberals are concerned.