GOP leaders wasted little time criticizing the AUMF for tying the hands of the Pentagon. And any administration effort to win GOP support by broadening the underlying war powers would only alienate more Democrats, thereby increasing the pressure on Pelosi to oppose a major piece of Obama’s foreign policy agenda.

Similar dynamics were on display in December, when Obama backed several Republican amendments to a sweeping year-end spending bill. Liberals in the House revolted and Pelosi sided with them, bucking Obama with a fiery floor speech condemning the package before voting against it. 

Adding to her challenge in the current debate, Pelosi rose to power, in part, on her staunch opposition to the George W. Bush administration’s invasion of Iraq in 2003. Indeed, Pelosi voted against the resolution that authorized that invasion even as the top Democrats in each chamber — Sen. Tom Daschle (S.D.) and Rep. Dick Gephardt (Mo.) — joined the Republicans in supporting it.