The measure took an important step when lawmakers voted to approve a rule, a necessary parliamentary step to bring the measure up. The vote was 242 to 192, with all 177 Republicans voting against it, a sign of GOP discipline and opposition. Some Democrats voted for the rule but probably will vote against the bill later. The vote came after President Barack Obama made a personal appeal, visiting with Democrats as the House began to discuss the bill in a rare Saturday session. 'We will vote today on the floor of the House of Representatives,' Majority Leader Steny H. Hoyer of Maryland said after the session with the president. Obama told Democratic members that he understood it would be a difficult vote for many of them, but he appealed to their sense of their own legacies, according to a leadership aide who was in the room. 'I'm absolutely confident we'll get this done,' Obama said, according to the aide. 'And when I'm in the Rose Garden signing a piece of legislation to give health care to all Americans, we'll look back and say this was our finest moment.' Obama struck the same themes when he spoke publicly in the Rose Garden before heading to Camp David. 'I just came from the Hill, where I talked to the members of Congress there, and I reminded them that opportunities like this come around maybe once in a generation,' Obama said. 'Most public servants pass through their entire careers without a chance to make as important a difference in the lives of their constituents and the life of this country. This is their moment, this is our moment, to live up to the trust that the American people have placed in us -- even when it's hard; especially when it's hard. This is our moment to deliver. 'I urge members of Congress to rise to this moment. Answer the call of history.' Earlier, the House began debate as Democratic Party leaders continued to work to round up the votes to pass the landmark measure. Rep. John Dingell, D-Mich., the longest-serving congressman, took the chair to oversee the highly partisan debate with a vote coming perhaps as soon as Saturday night. Democrats were still searching for the 218 votes they need to pass the legislation and have said the final vote could slip into Sunday or even early next week. Dingell, 83, joined the House in 1955, replacing his father, and has introduced his dad's national health insurance bill every year since. Dingell said many lawmakers have worked on the issue and added, 'The nation will be grateful to us all.' The early action on the floor was a parade of lawmakers asking for unanimous consent to introduce their remarks into the record. As each tried to add their political vision, Dingell snapped that they 'should not embellish their remarks with extended oratory,' a taste of the testiness expected throughout the day. Among other challenges, Republicans contend the health care bill is too expensive, piles on federal debt and is an opening to government control. Democrats reply that the bill would be a historic effort to increase the number of people who can get health care, create competition for those buying insurance and protect subscribers from harsh insurance company practices. The House bill would cost more than $1 trillion over the next decade, more than Obama has said was the limit and more than the cost of a bill working its way through the Senate. Eventually, all of the differences between the bills in the House and Senate will have to be reconciled before the measure hits Obama's desk. The most contentious issue is the type of public option to be offered. The House version includes a government-run insurance plan and a form of exchanges to give consumers more knowledge to make choices. This is a more robust public option version than the Senate's but far less than what liberals wanted. House Democrats are split on issues such as abortion, cost and immigration status. Late Friday night, House Speaker Nancy Pelosi worked out a compromise allowing Reps. Bart Stupak of Michigan, Brad Ellsworth of Indiana and other abortion opponents to insert tougher restrictions during Saturday's debate. Opponents say the amendment would restrict a woman's right to choose. Protesters carrying antiabortion signs chanted, 'Kill the bill. Kill the Pelosi bill!' when the president arrived. Eventually, Democrats hope to fashion a majority coalition to push the bill to conference committee, where the differences with the Senate version will be resolved. House Democrats hold 258 votes, meaning they can lose 40 votes and still have the 218 needed for passage. All 177 Republicans were expected to vote against the bill. House Minority Leader John A. Boehner, at a televised news conference, said of Republicans: 'We are going to do everything we can to stop this from becoming law.' Levey reported from Washington and Muskal from Los Angeles. 