The Senate will vote today on a "clean" spending bill that would fund the government without defunding the Affordable Care Act -- but House Speaker John Boehner, R-Ohio, says Republicans in the lower chamber won't sign off on the measure. White House officials say they'll allow a shutdown rather than negotiate on health care reform, which they believe would set a dangerous precedent. "The bigger danger for the president is to put himself in a position to be constantly held hostage. First, they want an arm. Then, they want a leg. It's unsustainable," said former White House adviser David Axelrod.