If any political prognosticators wanted proof that President Obama faces a tough sell on his health plan, they merely needed to show up at the National Constitution Center in Philadelphia yesterday.

A raucous standing-room-only crowd of more than 400 cheered, jeered, and booed Health and Human Services Secretary Kathleen Sebelius and U.S. Sen. Arlen Specter.

"I'm happy to see democracy is at work," Sebelius said, no detectable irony in her voice.

As each side battled for volume ("I think the boos were louder. That's my opinion," said one in the crowd, Diana Reimer of Lansdale), Sebelius and Specter managed, barely, to impose a tenuous civility on the hour-long meeting titled "Health Insurance Reform - What's in it for You."

"We can shout at one another, or we can leave the stage," Sebelius said. "It's up to you."

After an 11-hour session Friday, the House Committee on Energy and Commerce approved its version of landmark health legislation that could lead to coverage of 95 percent of Americans. It would also introduce a government-run insurance program that would compete with private plans.

When Congress returns in a month, that version must be blended with other House versions and then with whatever legislation makes it through the U.S. Senate.

Supporters yesterday hailed the idea of a new program that would cover 47 million uninsured Americans and provide broader access to medical care, particularly for those who have existing conditions and cannot get anything close to affordable insurance.

Many like the idea of single-payer insurance - a system in which all health-care costs are funneled through one agency instead of through multiple insurers. They applauded (and others, of course, booed) when Specter said he thought single-payer insurance should be on the table.

Generally, the boos came from people worried about rationing health care and committing the nation to an expensive health program it cannot afford.

Even before the event, tempers frayed. In the audience, Carol O'Brien, who called herself a Republican political junkie from Northeast Philadelphia, started talking about how adding 47 million uninsured people to the health-care system would strain it beyond capacity, causing long waits for service.

"I don't want to have to wait for care," O'Brien said. "I don't want the government dictating who will treat me and how they will treat me or if they will treat me."

Next to her, Susan Hoch listened until she couldn't help but interrupt. A rheumatologist at the University of Pennsylvania, she treats patients with rheumatoid arthritis and lupus. Too sick to work, when they lose their jobs, they also lose their insurance.

From there, she said, it's a medical and financial nightmare. "They can't get coverage," she said.

Soon O'Brien, her husband, John, and Hoch were arguing hard, interrupting, trying to out-talk the others - the whole health debate in three chairs on a balcony at the Constitution Center.

"A lot of people are worried about what will happen," Hoch said, her white physician's coat draped over the back of her chair. "I'm worried about what's happening now."

Shaking her head, O'Brien said, "Clearly I'm not going to change her opinion, and she's not going to change mine."

Among the naysayers who stepped up to the microphone was podiatric surgeon Jason Bell from Newark, Del., who said, "The American people don't want rationed health care."

Applause followed his remarks.

But Sebelius said health care was already rationed for the 12,000 people a day whose insurance disappears when they lose their jobs.

She was applauded, too.

The crowd included about a dozen people in wheelchairs wearing orange T-shirts who clapped when Sebelius spoke. Purple-shirted members of the Service Employees International Union broke into their "Yes, we can" chant. Alerted by e-mail, Physicians for Obama brought in some audience members.

On the boo side were dozens of people who pasted "Tell Washington No" bumper stickers on their chests. Reimer said her organization, the Philadelphia Tea Party Patriots, brought 40 people.

Outside, Reimer's allies won the poster battle, with messages such as "Government Health Care: Dangerous to Your Health" and "Welcome to the United States Socialist Republic," along with antiabortion signs.

Obama had hoped Congress would push through health legislation before its summer recess.

"I still remain confident that, at the end of the day, we will have a health-reform bill that passes by the end of the year and is signed by the president," Sebelius said before the meeting.

After the session, hustled out by security guards, she put a brave spin on the event.

"Health care touches everybody personally," she said, adding that, "I find it difficult," because so much misinformation gets repeated in questions at town-hall meetings.

"We have a challenge to get the message out."

Contact staff writer Jane M. Von Bergen at 215-854-2769 or jvonbergen@phillynews.com.