The UN mandate allowing US troops to occupy Iraq expires on December 31, 2008. So the Bush administration desperately wants to sign a bilateral agreement with the Iraqi government before that happens. Without one our presence will be blatantly illegal, without even a figleaf of international legitimacy, creating all kinds of trouble.
The problem for Bush is there’s more and more Iraqi resistance to signing anything, even among Nouri al-Maliki’s main supporters. Bob Fertik looks at the evidence here.