WASHINGTON - The White House called for a "simple up-or-down" vote on health care legislation Sunday as Speaker Nancy Pelosi appealed to House Democrats to get behind President Barack Obama's chief domestic priority even it if threatens their political careers.

In voicing support for a simple majority vote, White House health reform director Nancy-Ann DeParle signaled Obama's intention to push the Democratic-crafted bill under Senate rules that would overcome GOP stalling tactics.

Republicans unanimously oppose the Democratic proposals. Without GOP support, Obama's only chance of emerging with a policy and political victory is to bypass the bipartisanship he promoted during his televised seven-hour health care summit Thursday.

"We're not talking about changing any rules here," DeParle said. "All the president's talking about is: Do we need to address this problem and does it make sense to have a simple, up-or-down vote on whether or not we want to fix these problems?"

DeParle was optimistic that the president would have the votes to pass the massive bill. But none of legislation's advocates who spoke on Sunday indicated that those votes were in hand.

"I think we will get to that point where we will have the votes," predicted Sen. Robert Menendez, D-N.J., a member of the Senate Democratic leadership. "I believe that we will pass health care reform this spring."

In a sober call to arms, Pelosi said lawmakers sometimes must enact policies that, even if unpopular at the moment, will help the public. "We're not here just to self-perpetuate our service in Congress," she said. "We're here to do the job for the American people."

Pelosi said it took courage for Congress to pass Social Security and Medicare, which eventually became highly popular, "and many of the same forces that were at work decades ago are at work again against this bill."

It's unclear whether Pelosi's remarks will embolden or chill dozens of moderate House Democrats who face withering criticisms of the health care proposal in visits with constituents and in national polls. Republican lawmakers unanimously oppose the health care proposals, and many GOP strategists believe voters will turn against Democrats in the November elections.

Pelosi, from San Francisco, is more liberal than scores of her Democratic colleagues. But she generally walks a careful line between urging them to back left-of-center policies and giving them a green light to buck party leaders to improve their re-election hopes.

Her comments seemed to acknowledge the widely held view that Democrats will lose House seats this fall - maybe a lot. They now control the chamber 255 to 178, with two vacancies. Pelosi stopped well short of suggesting Democrats could lose their majority, but she called on members of her party to make a bold move on health care with no prospects of GOP help.