Amid fresh signs that the White House is preparing to back a scaled-down health care overhaul that would only include a public insurance option as a fallback plan, several House liberals told Roll Call that they could support such a bill depending on how it was structured.

The “trigger— approach has been considered a deal-killer by liberals on and off Capitol Hill, and the willingness of some Congressional Progressive Caucus members to entertain it reflects a recognition that a bruising August recess has imperiled prospects for reform and redrawn expectations for what is possible.

“This is a way to get a bill,— Rep. Bill Pascrell (D-N.J.) said. “I believe it’s worth listening to because I want legislation that is going to, in some shape or form, expand coverage and bring down the cost of health care.—

Liberals stressed that the shift does not amount to an abandonment of their commitment to a “robust— public insurance option. They said they would only support a trigger if that approach guaranteed the same access, quality and affordability.

“I don’t want to give the impression that I’m so flexible that I’m willing to compromise away meaningful reform,— Rep. Jim McGovern (D-Mass.) said. “But there may be a variety of ways of getting there than the one I originally formulated in my mind.—

The development could open a path forward for the White House, which has so far been vexed by the threat of a liberal rebellion in the House if it backs off a far-reaching public insurance option or a revolt by Senate moderates if it insists on one.

In advance of a make-or-break address to a joint session of Congress on Wednesday, President Barack Obama took the temperature of leading House liberals on a Friday conference call. Leaders of the Progressive Caucus, the Congressional Black Caucus, the Congressional Asian Pacific American Caucus and the Congressional Hispanic Caucus sat in on the call and reiterated their support for a strong public insurance option, Progressive Caucus Co-Chairwoman Lynn Woolsey (D-Calif.) said. Obama did not make any definitive statements and asked for a follow-up meeting today or Wednesday.

“It sounded like he was trying to figure out how he could get something he could call a public option, regardless of what it is,— one staffer familiar with the call said.

White House officials have been exploring the possibility of a trigger in negotiations with Republican moderate Sen. Olympia Snowe (Maine), a member of the gang of six on the Senate Finance Committee that has been struggling to forge a bipartisan agreement.

The Progressive Caucus has sent a series of letters warning the White House and House leaders to include a strong public insurance option as part of reform, including an Aug. 17 letter signed by 60 Members calling the public option “essential.— That’s more than enough to kill a health care overhaul given that no Republicans are likely to back it in the House.

Woolsey and Raúl Grijalva (D-Ariz.), co-chairman of the Progressive Caucus, sent Obama a letter Thursday indicating a compromise that House Energy and Commerce Chairman Henry Waxman (D-Calif.) struck with fiscally conservative Blue Dog Democrats on his panel was “unacceptable— because it untied the plan from Medicare reimbursement rates.

But while Progressive leaders have staked their caucus’s reputation on getting a strong public insurance option, vowing again and again that they will not cave, the rank and file aren’t necessarily holding the line.

“We’re the caucus that least marches to a unified drummer — that’s not what we do,— Rep. Mike Capuano (D-Mass.) said. “I’m serious about increasing access and quality, but that doesn’t mean it has to be a grand slam home run. I’ll take a ground-rule double if that’s what it takes. I’m happy to compromise if that’s what it takes. But compromise is compromise — it’s not rolling over.—

The question for liberals is what they have meant when insisting on a “robust— public insurance option, something Obama himself put to the caucus leaders on the Friday conference call, according to the aide. Progressive leaders have qualified it as a plan linked to Medicare rates and implemented without a trigger.

Rep. Jan Schakowsky (D-Ill.), an Obama ally, backed up that take in a Thursday statement declaring she would support “nothing short of a robust public health insurance plan upon implementation, no triggers.—  

Likewise, Rep. Lloyd Doggett (D-Texas), a signatory to the Progressive Caucus’ letters though not a member of the group, said that a trigger would “make it less likely that we have a robust public alternative— and that he would oppose it.

But the new openness by some liberals to at least entertain a trigger suggests it’s a movable standard.

“That’s why we used words like robust’ — because it’s in the eye of the beholder,— Capuano said. “We’ll make our independent judgments.—

If lawmakers agree to embrace the public option as a backstop, liberals want it to be a hair-trigger, more likely to be pulled than not.

Rep. Sam Farr (D-Calif.), a Progressive Caucus member, said he did not support the approach but did not foreclose on it, either. “It depends on how strong that trigger is,— he said. Farr said he has seen triggers implemented effectively in California. “Triggers work, but they’ve got to be really clear as to how they operate,— he said. “The only way I could see it getting progressive votes is by making sure the public option is strong and goes into operation.—

Either way, liberals interviewed for this story said they welcomed Obama’s decision to step into the thick of the debate and looked forward to hearing some clarity from him about his preferred approach. “Let him be straight with us,— Pascrell said.