Even as a wave of conservative protestors took over Capitol Hill, House Democrats' health care bill picked up the support of several influential organizations that could turn the tide in their favor among the most concerned groups: medical professionals and senior citizens.
President Obama this afternoon made a surprise appearance at the daily White House press briefing to thank AARP and the American Medical Association for throwing their weight behind the House Democrats' health care bill.
"When it comes to AARP, this is no small endorsement . ... They are a nonpartisan organization and their board made their decision to endorse only after a careful, intensive, objective scrutiny of this bill," the president told reporters. "The AARP knows this bill... is a good deal for our seniors, and that's why we're thrilled that they're standing up for this effort."
"Same is true for doctors and medical professionals supporting the bill," Obama added. "They would not be supporting it if they really believed that it would lead to government bureaucrats making decisions that are best left to doctors."
The president's remarks were directly pointed at critics who argue that Democrats' health care overhaul legislation constitutes a takeover of Americans' health care system.
"This bill is the greatest threat to freedom that I have seen," House Minority leader John Boehner, R-Ohio, told protestors gathered near the West Front of the Capitol chanting "Kill the bill."
But despite the public anger on display today, Obama expressed optimism that lawmakers are "closer to passing this reform than ever before."
The American Medical Association announced today that it will back the House bill, but warned that much more work needs to be done.
The legislation is "not a perfect representation of AMA views but consistent with our goals to warrant our support to keep the process moving," American Medical Association President James Rohack said in a conference call to reporters. "This legislation isn't perfect but this debate is not over."
When asked whether the organization has lost any members -- many doctors and medical organizations are opposed to some provisions in the bill -- Rohack said some members have indicated they will drop out but others have said they will join the association.
The AARP, which boasts some 40 million members and also faced backlash for its support of the legislation, also earlier today officially endorsed the House Democratic health care bill, saying it would close the coverage gap in Medicare prescription benefits, put strict limits on what health insurers can charge older workers too young for Medicare and create a voluntary, long-term care insurance program.
"We cannot continue to let insurers price older Americans out of the market, just as we cannot stand idle while millions of seniors are forced to choose between their groceries and their prescriptions," AARP chief executive Barry Rand said in a statement. "AARP is proud to endorse the Affordable Health Care for America Act and the Medicare Physician Payment Reform Act, and we urge members of the House to pass this critical package in the coming days to help fix our broken health care system."
The endorsement from what is considered to be the most influential seniors' lobby comes at a time when many seniors are concerned about the impact of Democrats' legislation on their health care plans. The House bill calls for steep cuts in Medicare.
ABC News' George Stephanopoulos reports that Speaker of the House Nancy Pelosi, D-Calif., and the Democratic leadership had been lobbying AARP for weeks. Officials of the organization also met Tuesday with White House Chief of Staff Rahm Emanuel and took the proposed endorsement to their board of directors.
AARP's support could provide fresh momentum to Pelosi's overhaul efforts as the Democratic leadership scrambles to get the 218 votes it needs to pass legislation on the floor.
The American Cancer Society Cancer Action Network, the advocacy arm of the American Cancer Society, also today backed the House Democrats bill, saying it will improve health care for cancer patients and their families.
"This legislation represents an exceptional opportunity to advance our mission of reducing suffering and death related to cancer," Chief Executive John R. Seffrin said in a statement.
House Democrats are determined to pass the $1.055 trillion, 10-year bill by the week's end, but they need the support of centrist Democrats, some of whom are skeptical about language on abortion and illegal immigrants.
No Republicans are expected to support the legislation, which, they still argue, entails a government takeover of Americans' health care system.
Today, the mood on Capitol Hill today was one of anger as "tea-party" protestors, led by Rep. Michele Bachmann's, R-Minn., came in droves and in buses from various states to protest Democrats' agenda. House Republican leadership also held a press event at noon to register their criticism.
"The Democrats do not have the American people and their best interest at heart," Linda Giresi, who came from Union, N.J., told ABC News. "They have their own self interests at heart. And that is the root of this 2,000 page outrage."
AARP Backs House Democrats Bill
Pelosi expressed confidence today that there will be enough votes to pass the bill, adding that she is "excited about being on the brink of passing historic health care legislation."
"We are on our path. We're very excited," she told reporters.
The speaker also hailed the support of the American Cancer Society while criticizing the large profits posted by some health care insurance providers like Cigna.
Majority Leader Steny Hoyer, D-Md., predicted that the House will pass overhaul legislation Saturday, but he admitted that it could be a close vote.
"I wouldn't refer to it as a squeaker, but I think it's going to be close," Hoyer said today in an interview with wire service reporters. "This is a huge undertaking."
Hoyer also said that the bill's endorsement by AARP was a significant boost. He added that the provisions on abortion and illegal immigrants were still being worked out but predicted those issues could be solved in time for Saturday's scheduled debate and vote.
House Democrats say their legislation would insure 36 million more people in the next 10 years, covering 96 percent of all Americans. That is more than the Senate bill currently being negotiated, which would cover an estimated 29 million additional people.
The House bill would also expand Medicaid coverage and provide more support to low-income citizens.
Democratic leaders argue that it would not add a dime to the deficit, an important factor considering President Obama has said he will not sign any legislation which does so.
Despite Pelosi's push to get health care legislation passed in the House, and the White House's confidence that it will get done by the year's end, senior Congressional Democrats have indicated that it is highly unlikely that a reform bill will be completed this year.
Senate Majority Leader Harry Reid, D-Nev., has yet to release the bill he eventually plans to bring to the Senate floor. Reid is still waiting for the Congressional Budget Office to come up with an estimated cost of several possible variations of his bill before deciding which one to introduce in the Senate.
Obama will meet with members of the House Democratic caucus tomorrow on the Hill to accelerate the momentum.
The Associated Press and ABC News' Jonathan Karl contributed to this report.