Capping 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 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 late-night arrangement covering abortion, Reps. Bart Stupak, Brad Ellsworth and other abortion opponents were promised an opportunity to try 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.

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. It effectively ended a standoff that dated to last summer, when the issue arose in one of three committees that debated the legislation.

There was no immediate reaction from prominent abortion rights supporters called to the late-night negotiations in the Capitol.

Dems 'very close'?
Separately, Pelosi and the leadership sought to ease concerns over illegal immigrants among Hispanic holdouts on the legislation.