Updated

Political pressure is being applied from all angles in Washington, as Democratic leaders scramble to close the deal on health care reform, and Republicans are being tapped to argue against -- and even in favor of -- the legislation.

Republicans in Congress are by all accounts united against the Democrats' proposal, the centerpiece of President Obama's domestic agenda. And on Saturday, the newest Republican member of Congress, Sen. Scott Brown of Massachusetts, targeted the legislation in the GOP's weekly address.

“For many members of Congress, the time for choosing is near: Do what the party leadership demands, or do what the people have asked you to do," Brown said. “If my colleagues don't mind some advice from a newcomer, I'd suggest going with the will of the people.”

It was Brown's victory in a special election in January that deprived Democrats of their supermajority in the Senate. Now Democratic leaders are trying to herd enough members together to pass the legislation with maneuvers to avoid a filibuster.

And the Democrats are getting a boost from a prominent former Republican representative -- a "life-long GOPer, fiscal conservative, 08 McCain supporter," White House Press Secretary Robert Gibbs boasted on Twitter.

That would be Transportation Secretary Ray LaHood, whose opinion piece supporting the Democrats' legislation appears in Sunday's Chicago Tribune.

"If I were still a member of Congress, I would proudly vote for the bill that President Barack Obama is championing and I would urge my colleagues to do the same, not because I don't believe in fiscal discipline, but because I do," LaHood said.

Whether LaHood's backing will persuade any Democrats -- let alone Republicans -- to vote for the legislation is anyone's guess. But both sides are pressuring the several Democrats on the fence about the proposals, in particular House Democrats who voted no on the health care bill last year.

The House and Senate both passed separate versions of a health care system overhaul, aiming to regulate insurance companies, lower health care costs and extend health care coverage to millions of uninsured Americans. But the two chambers weren't able to agree on and approve joint legislation before Brown's victory gave the GOP the ability to filibuster.

The Democrats' latest strategy is to have the House pass the Senate's bill as is, and then make the agreed-upon changes by passing a second bill through a maneuver known as reconciliation that would allow passage in the Senate with a simple majority, taking the filibuster out of the equation.

But that plan doesn't sit well for some Democrats in the House, because there may be no guarantee the second bill ever will be passed, leaving the Senate bill in place.

On Monday, President Obama will travel to Ohio to push for passage of health care legislation. In Ohio’s 16th Congressional District, Rep. John Boccieri, a freshman Democrat, is the target of a new Republican campaign ad. Boccieri voted no on the House bill last year but he is now wavering.

“I've stood up for my district. I voted against the first House version, I didn't think it went far enough,” Boccieri told Fox News.

Republican congressional candidate Jim Renacci has launched a new radio ad blasting Boccieri for recent statements saying he is considering voting for the health care legislation.

“Once again, John Boccieri is demonstrating that his loyalty lies not with the people of the 16th District, but with Nancy Pelosi and the far left,” says Renacci.

Boccieri counters, “I’m not afraid to cast a tough vote and I'm not afraid to stand up to leadership in doing so."

House Speaker Nancy Pelosi and other Democrats are predicting passage of the health care legislation in the next ten days, and some analysts agree.

"Some of the people oppose the bill because it doesn’t go far enough,” Democratic consultant Alicia Menendez told Fox News. “I think some of those people will get on board.”

But the outcome is far from certain, and Obama, urged on by Pelosi and Senate Majority Leader Harry Reid, has delayed his trip to Asia by three days. White House officials say the president has cleared that extra time in Washington to lobby members of Congress.

Fox News' Julie Kirtz contributed to this report.