WASHINGTON -- By late afternoon, Rep. Mike Doyle, D-Forest Hills, was looking weary.

As the point man to help strike a last-minute compromise on abortion language in the House of Representatives' health care bill, he was a busy legislator yesterday.

A vote on an overhaul of the nation's health insurance system is tentatively scheduled for this evening, but lingering concerns about abortion and illegal immigration threatened to keep Democrats from reaching the 218 votes needed for passage. No Republicans are expected to vote for the bill, meaning House Speaker Nancy Pelosi, D-Calif., can withstand no more than 40 defections from her caucus and still pass the legislation.

Many of those potential Democratic "no" votes are concerned about abortion. Federal law prohibits public funding for abortions, but the bill would subsidize people to purchase insurance plans that cover abortions from a newly created insurance exchange.

Rep. Bart Stupak, D-Mich., proposed an amendment that would not allow anyone with a government subsidy to purchase a plan that covers abortions, which rankled some in the party's pro-choice set.

So this week, Mr. Doyle, a pro-life Catholic, jumped in to try to appease both sides of the abortion debate.

He's been talking to members, leadership and the U.S. Conference of Catholic Bishops to try to find a deal.

The work appeared to pay off later in the evening as House Democrats said they cleared the impasse that had been holding up today's scheduled vote.

Late last night, Mr. Stupak said he and other abortion opponents will be given a chance to insert tougher abortion restrictions into the legislation during debate on the House floor.

The leadership hopes that no matter how that vote turns out, Democrats will then unite to give the health care bill a majority over unanimous Republican opposition.

"It's a very tricky balancing act," Mr. Doyle said earlier in the day yesterday, while taking a break outside the House floor.

"It's not a great job because you're back and forth to both sides, and when you're trying to find common ground, a lot of times both sides are saying you're not working in their interest. At times I've had both sides yelling at me."

The Conference of Catholic Bishops last week -- in an action it called "extraordinary" -- sent church bulletin inserts to nearly 19,000 parishes nationwide urging opposition to health care reform unless pro-life concerns are addressed. The conference expects the inserts to appear in bulletins in the next couple weeks.

But Mr. Doyle said the conference wants health care reform to pass and has been up-front in negotiations. It's different than dealing with members of Congress, though.

"When you're negotiating with the Catholic bishops, it's a little more difficult," he said.

Their blessing could be crucial to pass the legislation.

Rep. Jason Altmire, D-McCandless, said an endorsement from the bishops would make him "much more comfortable" -- but he said he still won't reveal his vote until he casts it.

Rep. Kathy Dahlkemper, D-Erie, a freshman who stressed her pro-life stance during her campaign, said abortion language is her primary reservation at this stage. Even though a provision she authored allowing young adults to stay on their parents' insurance until age 27 is in the bill, and she stood with Ms. Pelosi and spoke at a rally introducing the bill last month, Ms. Dahlkemper said she remains undecided on how she will vote.

The tension was palpable on Capitol Hill yesterday as Democratic leaders scrambled to corral their caucus and Republicans touted their unified opposition to the bill.

President Barack Obama is scheduled to come down Pennsylvania Avenue this morning to rally Democrats before a vote.

Mr. Altmire said that, aside from entreaties from the leadership, he fielded phone calls yesterday from presidential chief of staff Rahm Emanuel, Secretary of Health and Human Services Kathleen Sebelius, Secretary of Education Arne Duncan, and even Mr. Obama.

The presidential call lasted about 10 minutes, Mr. Altmire said, with Mr. Obama asking about his thoughts more than "giving me the hard sell."

"There is definitely a sense of urgency that you feel," Mr. Altmire said. "And I know I'm not the only member that's going through this."

Washington correspondent Daniel Malloy writes the "Pittsburgh On The Potomac" blog exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.