President Obama was in Ohio on Monday to give his third campaign-style, outside-the-Beltway health care overhaul sales pitch in the past half-dozen days.

But back in Washington, the furious action was behind the scenes, as Democratic leaders continued their desperate arm-twisting for health care’s too-close-to-call end game. And interest groups shoveled millions of dollars into last-ditch efforts to influence the outcome of the historic bill.

That outcome, which hinges on a key House vote expected later this week, remained wildly uncertain.

“Everyone knew it was going to be a nail-biter going into this,” says health analyst Alec Vachon. “It’s now all about vote wrangling.”

By The Numbers

To pass the health care overhaul, Democratic House Speaker Nancy Pelosi has to persuade at least 216 of her 253-member caucus to support the version of health care legislation that the Senate approved last December.

Among her formidable challenges: convincing recalcitrant House Democrats who find aspects of the Senate bill unpalatable that a subsequent smaller, so-called fix-it bill – known as reconciliation – will ultimately pass both chambers with at least some of their desired changes.

Health care overhaul advocates are banking on Pelosi’s powers of persuasion, as well as those of the president, to move enough Democratic fence-sitters to get to the magic 216 majority number.

Most vote counters say that as of Monday, Pelosi is still around a dozen votes short.

“There’s a path to victory for the Democrats, but a lot of things will have to go right,” says David Dayen, a blogger with the progressive Web site Firedoglake.

Dayen, who has been closely tracking the votes, says that Obama, Pelosi and Democratic leaders will have to persuade at least a half-dozen Democrats who voted “no” on the House version of health care legislation last fall to support the Senate version.

“That’s a tall order,” Dayen says.

One of those original “no” votes belonged to Ohio Rep. Dennis Kucinich, a hero to progressives who favors universal health care. He voted against the House bill last November because he said he viewed it as a sellout to Wall Street and the insurance companies.

Kucinich has said he’ll vote no again this week. And it just so happens that on Monday, Obama not only delivered his speech in the heart of Kucinich’s district but also met privately aboard Air Force One with the congressman and Ohio Rep. Marcia Fudge, who has not committed her vote.

Oddsmakers, no doubt, will be watching the two closely in coming days.

Also watching the horse trading for votes are investors who participate in the prediction market Intrade, which on Monday listed Obama’s health care legislation with a 70 percent chance of passing by June. That represents a significant increase from early this month, when it was listed with around a 30 percent chance.

High-Stakes Wooing

Private Air Force One meetings, behind-the-scenes deals, promises of something back home – the art of individual vote corralling takes many forms.

“It’s like romance – you say different things to different people,” says Vachon, the president of Hamilton PPB, which provides health policy advice to corporations and investors.

Vachon recalls that during the heated 2008 debate over the Bush administration’s Medicare prescription drug plan, he asked a member being courted by the White House whether he had asked for money for a bridge to be built back in the member’s district.

“He told me, ‘We don’t have a river,’ ” Vachon said. “I told him, ‘Hey, you could get that, too – go large!’ ” 

He was only half-joking.

There are at least a dozen House members who don’t like language in the Senate health care bill that limits federal spending on abortions because they believe it is weaker than House-approved language included in the so-called Stupak amendment.

But though Michigan Rep. Bart Stupak, who fashioned the amendment, has said that he’ll be a “no” vote this week, it appears that there are a handful of other Stupak amendment supporters who are moving to the “yes” category.

“It looks like Rep. Stupak is losing members. He said he had 12, but I only count six now as a firm ‘no,’ ” Dayen says. “And four or five are on the fence.”

Under the rules of reconciliation, Democratic leaders aren’t allowed to change the Senate’s abortion language because it doesn’t involve the budget. Instead, party leaders have been working to convince Stupak coalition members that the upper chamber’s abortion coverage provisions aren’t appreciably different than the House language.

But it leaves open the question of what promises Democratic leaders are making to sway members of Stupak’s coalition.

Vachon is among those who have long said that they believe Pelosi will find the votes – though he’s not sure how.

“This could be an epic fail – where she gets just 202 votes,” he says. “Or there could be the crowd effect” that will bring her a winning majority.

The Politics Of ‘No’

Still, the bottom line for many nervous House Democrats is how their health care vote will play back home in advance of the November elections.

And, of course, it depends on their district.

For some, voting against the health bill after they voted for it won’t win them any credit from opposition Republicans or the Tea Party movement. For others, pressure is being brought to bear by progressives and unions talking about backing potential primary challengers to Democrats who oppose the health care measure.

“There is a lot of pressure from all sides,” Dayen says.

Just ask Kucinich.

When Obama introduced Kucinich at Monday’s event, an audience member called out: “Vote yes!”

To which Obama replied: “Hear that, Dennis?”