This Yglesias post
has some interesting commentary on the Status of Forces Agreement the Bush administration is trying to force on Iraq:
I heard part of a conference call the National Security Network organized yesterday about the negotiations for a Status of Forces Agreement with Iraq. Skip Gnehm, who's been ambassador to Kuwait, Australia, and Jordan as well as a Deputy Assistant Secretary of State, a Deputy Assistant Secretary of Defense, and a number of other prominent positions made a couple of provocative points. One, he points out that "in all of my experience, there are no SOFA agreements that authorize military action." In other words, we have agreements with Germany, Italy, South Korea, Turkey, Saudi Arabia and other countries governing the presence of U.S. military forces in those countries, but none of them authorize the use of military force inside the host country or against the host country's citizens. Analogies between the SOFA the Bush administration is putting together with Iraq and standard alliance relationships are, in other words, totally invalid.