(CNN) - More and more, a possible compromise on how to overhaul the nation's ailing health-care system is taking shape.
Senators from both parties provided further clues Sunday to the potential form of a final agreement on the partisan issue that has sparked a heated nationwide debate, including last week's unprecedented heckling of President Barack Obama in Congress.
Two prominent senators said Sunday that a House health-care bill drafted by Democrats and vehemently opposed by Republicans and conservatives is dead. The senators - Democrat Kent Conrad of North Dakota and Republican Lindsey Graham of South Carolina - said on Fox News Sunday that any chance for a health-care overhaul focuses now on a compromise bill being negotiated by members of the Senate Finance Committee.
Another senior Demoratic lawmaker on Sunday promised that the Senate's health-care bill would include a public option that would have support from "some" Republicans.
"The bill - mark my word, I'm the chairman - is going to have a strong public option," said Sen. Tom Harkin, D-Iowa, who recently fill the late Sen. Ted Kennedy's seat as chairman of the Health, Education, Labor and Pensions Committee. Harkin was speaking to a supportive crowd at his annual steak fry fundraiser for Iowa Democrats.
Meanwhile, a moderate Republican senator considered one of the few who might cross the aisle to support health-care legislation being pushed by Democrats said she rejects a possible compromise provision - a trigger mechanism that would bring in a government-funded public health insurance option in the future if initial reforms fail to achieve specific thresholds.
Republicans unanimously oppose the public option as an unfair competitor that would drive private insurers out of the market, which they say would bring a government takeover of health care. Democratic supporters reject that claim as misinformation, saying a non-profit public option would be one choice for consumers who also could sign up for private coverage.
"The problem with the trigger is it just delays the public option," Republican Sen. Susan Collins of Maine told CNN's "State of the Union," explaining that the people who would determine whether creation of a public option gets triggered would be those who "want the public option."
The health-care debate entered a new phase last week with the return of Congress from its August recess and Obama's speech to a joint session of Congress last Wednesday.
Public concern, and in some cases outright hostility, over Democratic health-care proposals dominated many town hall meetings during the recess. Obama's speech presented his most detailed outline of possible legislation so far, but also produced an attention-grabbing moment when Republican Rep. Joe Wilson of South Carolina shouted "you lie" at the president.
Much of the anger focuses on a Democratic proposal, HR 3200, that was approved by the House Energy and Commerce Committee in July and includes the public option, higher taxes on the wealthiest Americans and other provisions opposed by Republicans and conservatives.
Obama's proposal, outlined in his speech, is similar to the compromise measure being negotiated by the six members of the Senate Finance Committee - three Republicans and three Democrats, including Conrad. The focus on the work by the negotiators, who expect their bill to be taken up by the full committee on Sept. 21, prompted Conrad and Graham to declare the House health-care legislation moot.
"It looks like the House bill is dead," Graham said. "It looks like all the action is now in the Senate."
Conrad agreed, saying "the only thing that has a prospect of passing" is the compromise that he and the other Finance Committee members are negotiating.
Conrad has proposed creating non-profit health insurance cooperatives as an alternative to the public option. Obama cited the approach as a possible middle-ground in his speech to Congress.
Graham, however, said Obama and Democratic leaders still are trying to do too much, too fast by proposing legislation that will cost $900 billion over 10 years. He rejected Obama's assertion that about half the costs can be covered by reducing fraud and waste in the government-run Medicare and Medicaid programs.
"No one's found them before," Graham said of such savings. "The only way you're going to find them now is to do something no one's been willing to do and that is to go in and change the system."
On the possible trigger mechanism for public option, Collins answered "no" when asked Sunday if she could support it. The idea was first proposed by her fellow senator and moderate Republican from Maine, Olympia Snowe, as a potential compromise for Republicans and moderate Democrats concerned about a public option.
Snowe, who is one of the six Senate Finance Committee negotiators, said Sunday on the CBS program Face the Nation that the proposal under consideration doesn't contain a trigger provision.
"It's not on the table, and it won't be," Snowe said. "We'll be using the (cooperatives proposed by Conrad) as an option at this point, as the means for injecting competition in the process."
However, moderate Democrat Sen. Mary Landrieu of Louisiana signaled her potential backing for a trigger provision, telling the ABC program This Week that she could "support potentially a fallback, but only if the private sector is allowed and given a great opportunity to get this right."
Obama and the Democrats have enough seats in both the House and Senate to pass a health-care bill without Republican support, but want some Republican votes to try to ease the partisan divide. Landrieu and other moderate Democrats in both chambers are considered the most crucial votes necessary to get a bill through Congress.
The next step is for both the House and Senate to pass bills in coming weeks, leading to a conference committee with members from both chambers who would negotiate a compromise proposal. Both the House and Senate would then have to approve the revised measure to send it to Obama for signing into law.
Snowe said the goal was producing a bill that could win support from Republicans as well as Democrats. She criticized what she called the "unfortunate and disgraceful" heckling by Wilson as a detriment to reaching a bipartisan agreement.
"I've served 16 years here and I've never witnessed that," Snowe said, later adding: "... Frankly, if there was more civility, we perhaps could get more done for the American people."
Wilson apologized last Wednesday for what he called inappropriate behavior, but maintains that Obama was wrong in saying his health-care proposal would not provide free health insurance for illegal aliens. On Sunday, Wilson said he won't apologize again on the House floor as demanded by House Democrats, who are threatening to censure him.
–CNN's Chris Welch and Martina Stewart contributed to this report.
Updated: 6:52 p.m.