US Foreign Policy discussion

I'm about to start reading by George Crile III. One of the inside cover quotes is by Chalmers Johnson, who is most famous for critiquing the "American Empire" in books like and . In the Los Angeles Times Book Review, he said "Crile's account is important, if appalling, precisely because it details how a ruthless ignoramus congressman and a high-ranking CIA thug managed to hijack American foreign policy." As I thought about Mr. Johnson's quote, it brought up two questions about U.S. foreign policy that I pose to you for discussion: first, who IS in charge of foreign policy? Is it the President, Congress, the military, the intelligence community? And second, who SHOULD be in charge of foreign policy? Should it be controlled exclusively by the executive branch or should Congress form an integral part in forming policy? Let me know what you think and if you have any books on this topic that you think would help, be sure to share.