WASHINGTON - A Republican senator seeking a bipartisan health deal spoke yesterday of "dialing down" expectations while one of President Obama's Democratic allies questioned whether the White House had the votes necessary for such a costly and comprehensive plan during a recession.

Obama's proposal to provide health insurance for 50 million Americans who lack it has become a contentious point for a Democratic-controlled House and Senate struggling to reach a consensus Obama desperately wants.

Much of the concern came after the nonpartisan Congressional Budget Office estimated that the plan would cost $1 trillion over 10 years and cover only about one-third of those now lacking health insurance.

Democrats protested that the estimate overlooked important money-savers to be added later. But Republicans seized on the costly projection and the bill's half-finished nature, throwing Democratic leaders on the defensive.

Sen. Chuck Grassley, the top Republican on the Finance Committee, said officials would have to rethink their best-case scenario for providing a sweeping overhaul of the health-care system at a relatively low price.

"So we're in the position of dialing down some of our expectations to get the costs down so that it's affordable and, most importantly, so that it's paid for because we can't go to the point where we are now of not paying for something when we have trillions of dollars of debt," said Grassley (R., Iowa).

Sen. Dianne Feinstein (D., Calif.) said she was uncertain there were enough votes in the president's own party to support the proposal.

"I think there's a lot of concern in the Democratic caucus," she said.

The overhaul's chief proponent in the Senate, Christopher J. Dodd of Connecticut, urged patience as lawmakers continued working on the bill.

But Sens. John McCain (R., Ariz.) and Lindsey Graham (R., S.C.) said the bill's cost was problematic.

"You do the math," McCain said. "It comes up to $3 trillion [to cover all 50 million uninsured]. And so far, we have no proposal for having to pay for it."

The CBO estimates "were a death blow to a government-run health-care plan," Graham said. "The Finance Committee has abandoned that. We do need to deal with inflation in health care, private and public inflation, but we're not going to go down to the government-owning-health-care road in America, and I think that's the story of this week. There's been a bipartisan rejection of that."

Competing plans abound in Congress, complicating Obama's task.

"As a matter of fact, I don't have the slightest idea what is in either of the two bills in the committees," said Sen. Richard G. Lugar (R., Ind.). "None of us do because much of it hasn't been written, still being drafted. People are scoring something that doesn't exist. What I would suggest is we hang on now for a period of study so that we find literally what the alternatives are."

As for his favored outcome, "I think it should be incremental steps," Lugar said.

Health-care changes have widespread public support, according to a CBS-New York Times poll released Saturday. Almost two-thirds say the government should guarantee health insurance for all Americans while half that many say it is not the government's responsibility.

People are more divided when it comes to such a program's effect on the economy and whether they are willing to pay higher taxes so all Americans have health care.

Feinstein, Lugar, and Grassley spoke to CNN's State of the Union. McCain appeared on CBS's Face the Nation, and Graham on ABC's This Week.