About 25 House Democrats are undecided on how they will vote. They want firm assurances from the Senate that they will pass the same health care bill. So far, Senate Democratic leaders have 41 votes, and they need 51 to pass the bill through a process called reconciliation.
President Obama has ratcheted up the pressure on undecided Democrats, personally reaching out to those party members in the House who are still undecided or are vowing to vote "No."
In an interview with Fox News Wednesday, the president appealed to the constituents of conservative House Democrats to urge them to vote "Yes."
"What I can tell you is that the vote that's taken in the House will be a vote for health care reform. And if people vote yes, whatever form that takes, that is going to be a vote for health care reform. And I don't think we should pretend otherwise," Obama said in an interview with Fox News' Bret Baier. "If they don't, if they vote against, then they're going to be voting against health care reform and they're going to be voting in favor of the status quo.
"So Washington gets very concerned about these procedural issues in Congress. This is always an issue that's -- whether Republicans are in charge or Democrats in charge -- when Republicans are in charge, Democrats constantly complain that the majority was not giving them an opportunity, et cetera," he added.
The president was referring to the controversy surrounding the parliamentary procedure Democrats may use if they cannot get the 216 votes they need.
The earliest the bill could be passed at this point is Sunday as the Congressional Budget Office has yet to release its cost estimate.
If they are not able to garner enough votes, Democratic leaders have hinted they may employ a parliamentary maneuver dubbed as "deem and pass."
The controversial procedure would allow House members to vote on health care changes without ever voting directly on the Senate bill. In this case, the House would vote on a "fix it" measure that would make changes to the Senate health care bill and then automatically, in the process, pass the bill without actually having to vote on it.
The procedure has been used 20 times over the last 30 years by both Democrats and Republicans, often on technical or unpopular measures like raising the debt limit, but never on one as big as health care reform.
Vice President Biden joked about the difficulties of tackling the health care bill at the annual Radio-TV Correspondents dinner Wednesday evening.
"Trying to negotiate a lasting peace between the Palestinians and Israelis is tough. But it was a hell of a nice break from health care," Biden quipped.
Members of Congress are under increasing pressure from all sides on the health care bill. Altmire has not only received calls from the president, he was confronted by tea party activists at his office, demanding an answer on how he will vote.
At the same time, some union leaders are telling wavering Democrats that if they vote against the health care bill, they might not get any union support in November's mid-term election.
"We're telling them that we supported them on that basis and if they can't stand up for their promises, then we have to consider what else we can do," said Andy Stern, president of the Service Employees International Union.
Others are making a much darker prediction about what the health care debate could do to Obama's presidency.