WASHINGTON -- The second-ranking House Democrat predicted that historic health care legislation will be passed Saturday, extending coverage to tens of millions of uninsured and banning the industry from turning people away.

Rep. Steny Hoyer told reporters House leaders would have the 218 votes needed to pass the sweeping bill that President Obama has made the defining social goal of his young administration -- presuming a couple of final issues are resolved. Hoyer acknowledged that the vote could be tight.

"I wouldn't refer to it as a squeaker, but I think it's going to be close," Hoyer said. "This is a huge undertaking."

The Maryland Democrat said language on abortion and illegal immigrants was still being worked out, but predicted those issues could be solved in time for Saturday's scheduled debate and vote on the 10-year, $1.2 trillion legislation.

"We certainly have well over 218 people who say they want to vote for the bill," Hoyer said in an interview with wire service reporters.

"The trick is making sure they have a comfort level with the provisions they are particularly focused on to allow them to do so," he said. "So I think that's what we're in the final stages of trying to get to."

Obama planned a rare trip to the House on Friday to try to win over wavering lawmakers.

Hoyer also said that the bill's endorsement by the powerful seniors' lobby AARP, announced Thursday, was a significant boost. The American Medical Association also announced Thursday that it would back the bill.

AARP Senior Policy Adviser John Rother said the 40-million strong organization favors the House bill because it closes the coverage gap in Medicare prescription benefits, puts strict limits on what health insurers can charge older workers too young for Medicare and creates a voluntary, long-term care insurance program.

The American Cancer Society Cancer Action Network also announced its support for the legislation Thursday, and the American Medical Association, which had endorsed an earlier version of the bill, scheduled a midday press call to weigh in.

Action is slower on the other side of the Capitol, where senators are awaiting an analysis from the Congressional Budget Office on legislation written by Senate Majority Leader Harry Reid and others. The timeline there appears likely to spill into next year.

The AARP's backing is a big boost for the House effort. Support from this group proved a crucial stamp of approval when then-President George W. Bush pushed the Medicare prescription drug benefit through a closely divided Congress in 2003.

But strong opposition remains on Capitol Hill.

Republican leaders were scheduled to appear outside the Capitol at a rally opposing the legislation, a protest led by anti-big-government "tea party" activists.

With no GOP backing, Democrats will need overwhelming support from within their own caucus. An intraparty disagreement over how to prevent federal funds from being used to pay for abortion has not yet been entirely resolved, though Hoyer said that language being circulated by one anti-abortion Democrat, Rep. Brad Ellsworth of Indiana, seemed likely to be the basis for an agreement.

Ellsworth's language aims to strengthen stipulations already in the bill against federal money being used to pay for abortions. It would still allow people to pay for abortion coverage with their own money.

That distinction doesn't satisfy anti-abortion groups, which dismiss it as an accounting gimmick. They say federal subsidies for insurance coverage would not be clearly segregated from private funds used to pay for abortions.

The National Right to Life Committee issued a blistering press release Wednesday night calling Ellsworth's proposal "a political fig leaf made out of cellophane."

Ellsworth said that didn't bother him: "I know what's in my heart, I know what's in my head and I think the big guy upstairs knows," he said.

House leaders are also still grappling with illegal immigration, specifically whether illegal immigrants -- who would be barred from getting federal subsidies -- should be able to purchase insurance coverage within new government "exchanges," using their own money.

The White House does not want this allowed, but some members of the Congressional Hispanic Caucus and other Democrats view that position as too extreme. Hispanic Caucus officials were scheduled to meet with Obama at the White House on Thursday.

The House bill would provide government subsidies beginning in 2013 to extend coverage to millions who now lack it. Self-employed people and small businesses could buy coverage through the new exchanges, either from a private insurer or a new government plan that would compete. All the plans sold through the exchange would have to follow basic consumer protection rules.

Meanwhile, the CBO released an analysis of the House GOP bill that found it would reduce the number of uninsured by just 3 million in 2019. By comparison, the more expansive Democratic bill would gain coverage for 36 million.

While the Democrats' bill would cover 96 percent of eligible Americans, the Republican alternative would cover 83 percent -- roughly comparable to current levels. The budget office said the Republican plan would reduce federal deficits by $68 billion over the 10-year period and push down premiums for privately insured people.