How Long Will the US Stay in Iraq?

American forces are in Iraq under a United Nations mandate that runs out at the end of this year. Barack Obama wants to withdraw American forces within 16 months after taking office. John McCain says that would be trading victory for defeat. Now US Senators of both parties claim the Bush Administration is negotiating agreements with Iraqi officials that could tie the next president's hands. While the Bush White House says it's all "technical" and non-binding, it's highly controversial in Iraq. Is the US trying to establish permanent bases without the consent of Congress? What would that mean for Iraqi sovereignty, Iran and US allies like Egypt and Saudi Arabia? How would it influence the presidential campaign?