WASHINGTON - Pushing toward a history-making vote, Democrats struggled to eliminate lingering complications standing in the way of House action this weekend on President Barack Obama's landmark health care overhaul.

Their drive to make the nation's health care system more efficient and extend coverage to millions of uninsured Americans took on a growing sense of inevitability, picking up endorsements from a longtime liberal holdout and from a retired Roman Catholic bishop and nuns who broke with church leaders over the bill's abortion provisions.

At the same time, last-minute snags related to costs delayed formal release of the legislation and an analysis from the Congressional Budget Office at least until Thursday. Democratic lawmakers had hoped to see those details last week.

Since Democrats are promising 72 hours for lawmakers and the public to review the legislation once it's released, that would push a House vote on the bill until Sunday at the earliest -- the same day Obama plans to leave for an overseas trip. Obama already has delayed the trip once so he can be present for the vote and help with the 11th-hour arm-twisting that inevitably will precede it.

"You've got to realize how complicated this is and how focused we are on getting it right," House Majority Leader Steny Hoyer, D-Md., said Wednesday near the end of a long day of meetings on the legislation. "We're waiting to get a real confidence level."

Obama expressed optimism in an interview with Fox News Channel. "I'm confident it will pass," he said. "And the reason I'm confident that it's going to pass is because it's the right thing to do."

Democrats are seeking to make sure the legislation would reduce federal deficits annually over the next decade and are revisiting details of a planned tax on high-cost insurance plans that's been a sticking point for organized labor. Richard Trumka, head of the AFL-CIO, met with Obama at the White House on Wednesday, and officials said the labor leader raised concerns. Obama has proposed significantly softening the tax in keeping with an earlier deal with organized labor, and labor leaders want to preserve that accord, at a minimum.

Trumka was to brief members of the AFL-CIO's executive council on Thursday, and the federation was expected to announce whether it would support the legislation.

The long-anticipated measure is actually the second of two bills that Obama hopes lawmakers will send him in coming days, more than a year after he urged Congress to remake the U.S. health care system. The first cleared the Senate late last year but went no further because House Democrats demanded significant changes — the very types of revisions now being packaged into the second bill.

Together, the measures are designed to extend coverage to more than 30 million who now lack it and prohibit insurance industry practices such as denying coverage on the basis of pre-existing medical conditions. Obama also has asked lawmakers to slow the growth of medical spending generally, a far more difficult goal to achieve. The total cost is around $1 trillion over 10 years.

After heavy lobbying from Obama, liberal Rep. Dennis Kucinich, D-Ohio, announced his support Wednesday, becoming the first Democrat to declare he would vote in favor of the legislation after opposing an earlier version. Shortly after Kucinich's announcement, a letter was released from 60 leaders of religious orders urging lawmakers to vote for the legislation.

The endorsement reflected a division within the Catholic Church. The U.S. Conference of Catholic Bishops opposes the Senate-passed legislation, contending it would permit the use of federal funds for elective abortions.

Late Wednesday, however, retired Bishop John E. McCarthy of Austin, Texas, told The Associated Press he was urging approval of the legislation.

"The bill guards against the use of federal money for abortion," McCarthy said in an interview. "This is an extraordinarily important bill, providing health care for 30 to 40 million people who don't have it. It's not perfect; we can come back later and improve it. But let's not kill it at this crucial moment." McCarthy, 80, served as bishop of the Austin diocese from 1986-2001.

Reflecting growing opposition among states to the health care bill, Idaho Gov. C.L. "Butch" Otter, a Republican, signed a measure Wednesday requiring the state attorney general to sue the federal government if residents are forced to buy health insurance. Similar legislation is pending in 37 other states.