Blowback is a 2004 lecture by Chalmers Johnson on the US Empire. Drawing comparisons with Rome, Johnson describes the end of the Republic through imperialism and militarism.
Blowback (57:00): MP3
The core of Johnson speech is on American militarism but discussing Iraq he explains the influence of the neocons as the main reason for war (although perhaps also overstating the case of oil politics too).
There is ample evidence that within this group [the Neoconservatives], and I’m not in any sense trying to be anti-israeli because I’m in fact quite alarmed by the dangers Israel is in today, but that many of these people have very close ties to the right-wing of the likud party, I mean close ties to Benjamin Netanyahu of which they have written papers for him, they’re personal associates of his, and things of this sort, and much of what they stand for does reflect the particular views of the sharonistas, if you will, that it serves their interests to destroy Iraq even if it has not particularly served ours.
The United States operates hundreds of military bases around the world. It’s a form of colonialism that is expanding under the Bush Administration’s post-9/11 doctrine of pre-emptive war. Supporting a far-flung military empire generates large profits for many US-based corporations. It’s terrific for weapons manufacturers like Lockheed Martin and Northrop Grumman and for support contractors like Halliburton. Increasingly, many people worldwide are angry with having to live with Uncle Sam in uniform in their backyard.
Chalmers Johnson
Chalmers Johnson is the author of the national bestseller Blowback. He is the president of the Japan Policy Research Institute and professor emeritus at the University of California, San Diego. His latest book is Sorrows of Empire: Militarism, Secrecy and the End of the Republic.
P U L S E 
Q & A following this lecture can be heard here. and in the following videos.