WASHINGTON (CNN) -- President Barack Obama will meet with members of the House Democratic caucus Saturday in a rare visit to Capitol Hill as he works to push forward proposed health care legislation.
But the contentious issue of abortion is threatening to delay Saturday's scheduled vote on the nearly $1.1 trillion health care bill by the full House of Representatives and possibly push it back to Sunday, according to two Democratic sources.
In a late night development, anti-abortion Democrats scored a major victory by persuading Democratic leaders to allow them to offer an amendment during the House health-care debate Saturday that would ban most abortion coverage from the public option and other insurance providers in the new so-called "exchange" the legislation would create, three Democratic sources told CNN.
The prohibition would exclude cases of rape, incest or if the mother's life is in danger.
House Democratic leadership sources said that win or lose, they hope giving abortion foes the opportunity to vote will clear the way for passage of their health care bill. But sharp differences among Democrats on the abortion issue and others, such as immigration, are raising questions over whether Speaker Nancy Pelosi currently has the 218-vote majority needed for passage of the legislation.
Several anti-abortion Democrats will offer the amendment, including Rep. Brad Ellsworth, D-Indiana, and Rep. Bart Stupak, D-Michigan.
The fact that the amendment will be allowed to be proposed is also a big win for the U.S. Conference of Catholic Bishops, which used its power -- especially with conservative Democrats in swing congressional districts -- to help force Democratic leaders to permit a vote that most of them oppose.
"We didn't have a choice," said a Democratic leadership source. "We didn't have the votes" on health care without agreeing to this.
Planned Parenthood decried the amendment, saying it would result in the elimination of abortion coverage currently offered by most private health insurance plans.
"This amendment would violate the spirit of health care reform, which is meant to guarantee quality, affordable health care coverage for all by creating a two-tiered system that would punish women, particularly those with low and modest incomes," the group said in a statement.
"Women won't stand for legislation that takes away their current benefits and leaves them worse off after health care reform than they are today."
The Democratic sources said people would be able to purchase riders with their own money for insurance that includes abortion coverage.
Stupak and other anti-abortion Democrats have argued for a strict abortion ban for some time.
However, Ellsworth had offered a less strict compromise measure that would have prohibited taxpayer dollars for abortions.
But Liz Farrar, a spokeswoman for Ellsworth, told CNN that some two dozen Democratic lawmakers made it clear that they needed assurances from the Catholic bishops before they could sign on -- and that the religious group made clear it wanted to bolster the abortion restrictions.
House Speaker Nancy Pelosi and other leaders were negotiating with the Catholic bishops and their representatives on Friday.
Late-night marathon talks in the speaker's office included staunch supporters of abortion rights, but they broke down.
"We came to the point where we actually had an agreement tonight, but it fell apart," Stupak said.
As Stupak offered the amendment before the House Rules Committee, several abortion rights activists on the panel argued the amendment goes too far.
"I find this amendment very, very uncomfortable," said Rep. Jim McGovern, D-Massachusetts.
"I foresee for poor women in America, a return to the dark ages," said Rep. Alcee Hastings, D-Florida.
Republican leaders added to the turmoil surrounding the bill Friday morning, seizing on news of spiraling unemployment to warn that new taxes and regulations including in the sweeping reform measure would push the country into an economic abyss.
At the same time, members of the Congressional Hispanic Caucus staunchly oppose adding a provision to the bill that would bar undocumented workers from using their own money to buy health insurance policies available through the exchange.
The measure is already included in the Senate Finance Committee's version of the bill, and is backed by the White House. Some conservative House Democrats have also indicated their support for the Senate language.
Several Hispanic Caucus members who discussed the issue with Pelosi Friday said they had received assurances the Senate language would not be included. Rep. Charlie Gonzalez, D-Texas, warned Thursday that several caucus members might try to block the House bill if it's changed to conform to the Senate measure.
"I understand the politics of it, but it is very bad policy and I'd love, for once, the policy to trump the politics," he said.
Pelosi's bill currently includes various requirements for immigrants to verify their citizenship before getting federal subsidies to buy health insurance. Conservatives, however, have called the requirements insufficient.
Many conservatives, particularly on the Republican side of the aisle, also continued Friday to raise questions about the overall cost of the bill.
"The speaker's bill includes job-killing taxes and mandates that will hurt small businesses," House Minority Leader John Boehner said Friday. "For the sake of our families and small businesses, this job-killing bill needs to be defeated."
But some so-called Blue Dog Democrats are among those who intend to vote "no," including Rep. Stephanie Herseth Sandlin, D-South Dakota, and Rep. Frank Kratovil, D-Maryland.
"The overall cost of it is substantial," Kratovil told CNN.
The House bill would extend insurance coverage to 36 million uncovered Americans and guarantee that 96 percent of Americans have coverage, according to the non-partisan Congressional Budget Office.
Among other things, the bill would subsidize insurance for poorer Americans, establish a new government-run public option and create health insurance exchanges to make it easier for small groups and individuals to purchase coverage. It would also cap annual out-of-pocket expenses and prevent insurance companies from denying coverage for pre-existing conditions.
Pelosi's office has said the bill would cut the federal deficit by roughly $30 billion over the next decade. The measure is financed through a combination of a tax surcharge on wealthy Americans and spending constraints in Medicare and Medicaid.
The bill received a major boost Thursday when it was endorsed by AARP and the American Medical Association.
AARP, the nation's largest organization of older Americans, is a non-partisan group that advocates for people over the age of 50. The AMA, historically an opponent of health care reform, is considered one the nation's most influential doctors' advocacy groups.
-- CNN's Dana Bash, Lisa Desjardins, Alan Silverleib, Paul Steinhauser
and Deirdre Walsh contributed to this report.
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