WASHINGTON - Capping months of months of struggle, Democrats in the House of Representatives cleared an abortion-related impasse blocking a vote on sweeping health care legislation late Friday and officials expressed optimism they had finally lined up the support needed to pass President Barack Obama's top domestic priority.

A vote was expected on the legislation on Saturday, after Obama's scheduled midmorning trip to the Capitol complex to make one final pitch for its approval. The bill is designed to spread coverage to tens of millions who now lack it and ban insurance industry practices such as denying coverage on the basis of pre-existing medical conditions.

Under the arrangement, Reps. Bart Stupak, Brad Ellsworth and other abortion opponents were promised an opportunity to insert tougher restrictions into the legislation during debate on the House floor.

The leadership's hope is that no matter how that vote turns out, Democrats on both sides of the abortion divide will then unite to give the health care bill a majority over unanimous Republican opposition.

The plan emerged from hours of meetings presided over by House Speaker Nancy Pelosi and involving lawmakers on both sides of the abortion issue and officials from the U.S. Conference on Catholic Bishops.

Separately, Pelosi and the leadership sought to ease concerns among Hispanic holdouts on the legislation.

"We're very close" to having enough votes to prevail, Majority Leader Steny Hoyer said in a midday assessment, although he cautioned at the time that a scheduled Saturday vote could slip by a day or two and sought to pin the blame on possible Republican delaying tactics.

"Nice try, Rep. Hoyer, but you can't blame Republicans when the fact is you just don't have the votes," shot back Antonia Ferrier, spokeswoman for the Republican leader, Rep. John Boehner.

Hours later, Democrats were still trying to get them.

In a midnight-hour appearance before the House Rules Committee, Stupak said he hoped the House would pass a ban any abortion benefit from being offered in a government-run insurance option that is envisioned under the bill, except in instances of rape, incest or when the life of the mother was in danger.

Separately, he said that he and his allies wanted a similar ban on coverage under policies offered by private insurers in a federally regulated exchange that would be created.

Stupak also said attempts during the evening to reach a compromise that both sides could support had ultimately collapsed.

"I think we have a fundamental disagreement in this issue. That's a reality," Rep. Henry Waxman, a supporter of abortion rights, said after hours of closed-door talks on the issue.