WASHINGTON — President Barack Obama and Democratic leaders lobbied intensively for historic health care legislation Friday, striving to resolve a last-minute dispute over Medicare while gaining another precious "yes" 48 hours ahead of a climactic vote.

With a showdown set for Sunday on the House floor, Democratic leaders still didn't command the 216 votes they needed, so every undecided lawmaker was the focus of personal attention from House Speaker Nancy Pelosi and the White House.

Obama, who delayed an overseas trip to help ensure passage of the legislation, planned to meet with Democratic lawmakers at the White House Saturday afternoon.

In an 11th-hour pitch, the president spoke to an enthusiastic crowd at George Mason University in Virginia, lobbing attacks at the insurance industry with his coat jacket off and sleeves rolled up.

"The only question left is this: Are we going to let the special interests win once again, or are we going to make this vote a victory for the American people?" he said.

Obama described the stakes in stark terms, using words uttered so rarely out of the White House that they seem all but banned: "If this vote fails." What then? "The insurance industry will continue to run amok," the president said, pointing to rising rates, denials of coverage and limits on care.