"I am absolutely confident that if the American people know what's in this bill, and the Senate knows what's in this bill, it will pass, because it's right for America," the president said.
"We simply cannot allow differences over individual elements of this plan to prevent us from meeting our responsibility to solve a longstanding and urgent problem for the American people. They are waiting for us to act."
White House officials say Obama made the case to Democrats that this might be the last chance to make progress on health care overhaul before the 2010 elections, and before his political capital possibly diminishes later in his first term.
For congressional Democrats, deep differences remain on the so-called Medicare buy-in, which, if included, would have allowed Americans between the ages of 55 and 64 to buy into Medicare. However, the central tenets of that compromise reached last week between Democrats were stripped from the bill because of the objections of independent Sen. Joe Lieberman of Connecticut, who said he would not support the legislation if it contained that option "because it reportedly has some of the same infirmities that the public option did."
Democratic leaders need Lieberman's vote to avoid a Republican filibuster, but liberals are unhappy, saying the bill has been gutted to please one senator.
All eyes are also on Sen. Ben Nelson, D-Neb., whose amendment to impose tighter regulations on abortion coverage was voted down earlier this month. Democrats are counting on his support to get the needed 60 votes but he has not said how he will vote.
There's unlikely to be any Republican support. Even moderate Sen. Olympia Snowe of Maine, who had been working with Democrats for months, said she can't support the bill in its current form.