Rarely in the spotlight, and unfailingly restrained, the Delaware Democrat never staked out a public position on the government insurance option, solidifying his status as the model of an undecided moderate in need of persuading.

But now, Carper is emerging as a backroom mediator on the most divisive element of the health care overhaul, proposing a so-called third way that several key senators said Wednesday could provide the blueprint for compromise in the Senate bill.

Carper wants to allow states to individually decide whether to create a private-insurance competitor such as a government plan and a nonprofit insurance cooperative, or to open up state-based insurance pools for government workers to every resident.

It could appeal to Sen. Olympia Snowe (R-Maine), who has endorsed a similar trigger approach, while bringing in progressives who may not see a way – at this point – to pass a bill through the Senate with a public option.

All while publicly proclaiming to be agnostic on the government option, Carper has buttonholed President Barack Obama several times, shopped a one-page explainer to his Finance Committee colleagues, and huddled with Snowe. He began formulating his plan several weeks ago, and has been quietly talking it up since then.

“One thing I have focused on is to get Democrats and Republicans to work together on thorny divisive issues,” Carper said Wednesday. “And this is an area where we need to get a consensus.”

With discussions that evolve daily, there is no way to predict with certainty what Senate Majority Leader Harry Reid (D-Nev.) will include in the merger of two competing bills from the Senate Finance and health committees.

But the Carper option - or some variation of it - could be right at this stage of the process, senators said.

Public option proponents have not yet shown that they can get 60 votes in the Senate. Sen. Kent Conrad’s proposal for a network of cooperatives never caught on with Democrats beyond the Finance Committee. And the White House has sent cryptic, if not steady, signals that it views a form of Snowe’s trigger option as its own kind of fallback plan.

“I think perhaps it could” emerge in the Senate bill that heads to the floor, Conrad said. Finance Chairman Max Baucus (D-Mont.) said the idea is under discussion, and “might be” what Reid goes with. Sen. Ron Wyden (D-Ore.) called the the proposal “intriguing.”

“It is very constructive option,” Conrad said.

Carper’s plan is one of several alternatives emerging from the fractious debate over the public option. Sen. Maria Cantwell (D-Wash.) filed an amendment giving states the power to work with private insurers on expanding coverage up to 200 percent of poverty, which would cover about 75 percent of the uninsured.

Carper’s proposal is, in some ways, more conservative than the “trigger” option offered by Snowe.

Under Snowe’s proposal, a new national nonprofit corporation would offer insurance in any states where affordable coverage was not widely available from private insurers. Federal officials would serve on the corporation’s board, but it would not be part of the Health and Human Services Department.

Carper’s proposal would leave decisions and solutions up to the states. While Snowe’s amendment sets only an affordability test for the trigger, Carper would allow states to opt-in if affordable insurance is not widely available or the insurance market is dominated by only one or two players.

“I see a menu of options for states to consider in states where there is no meaningful competition,” Carper said.

The federal government would offer seed money, and there is already $6 billion in the bill for the co-ops, Carper said.

Neither Carper nor Snowe is expected to offer their proposals during the Finance Committee markup, which could conclude as early as Thursday. Both senators seem to have made the calculation that their ideas would get a more receptive audience later in the process.

Like almost every other potential alternative to the public plan, Carper’s proposal may not break the impasse.

Snowe, who said she is talking with Carper, has reservations about allowing states to create their own government-run insurance plans. “I am just concerned that is another backdoor route,” Snowe said.

Sen. Susan Collins (R-Maine) said Maine created a state government option, and it hasn’t been successful.

“So my experience has not been a very good one,” she said. “I will look at it but it doesn’t sound like something I will support.”

Sen. Debbie Stabenow (D-Mich.), a public plan supporter, said Carper’s proposal was unlikely to be an adequate substitute. Sen. Robert Menendez (D-N.J.) said he doesn’t know “at the end of the day if it really meets the goal that those of us who support the public option really want to see.”

Sen. Mark Pryor (D-Ark.), another key moderate, said he is open to the idea, but he is also remains open to a public option, depending on the way it is structured.

But at this point, Reid and the White House are looking for a way to get the bill to the Senate floor – and this could be the middle ground they need, aides said.

The tough negotiating – and the hard sell for what they really want – is on hold until the conference committee.