House liberals are warning the Senate, Democratic leaders and President Barack Obama that a government-run insurance option must be included in any health reform bill, or else the powerful bloc will vote it down.

“Usually, we work behind the scenes to strengthen legislation,— said Rep. Lynn Woolsey (D-Calif.), co-chairwoman of the 80-member Congressional Progressive Caucus. “We’re careful not to take on our party’s leadership, or President Obama.

“This time, however, is different.—

Woolsey made it clear that she and many of her colleagues will vote to kill a health care plan if it leaves patients at the mercy of private health insurance companies.

“No one in this building wants health care reform as much as we do. However, if reform legislation comes to the floor, and it does not include a real and robust public option that lives up to our criteria, then we will fight it with everything that we have,— she said.

The draft House bill presented last week includes such a public option, which is supported by Speaker Nancy Pelosi (D-Calif.) and Obama, but it faces resistance from fiscally conservative Blue Dog Democrats and a rocky road in the Senate.

Woolsey spoke at a Wednesday joint press conference featuring the Progressive Caucus, the Congressional Black Caucus, the Congressional Hispanic Caucus and the Congressional Asian Pacific American Caucus.

The intraparty groups demanded a national Medicare-like public insurance option for everyone that would compete with private insurers, and urged the Senate to come aboard. “I would suggest that they look at the polls,— said Rep. Mike Honda (D-Calif.), chairman of CAPAC, noting support for a public option at above 70 percent.

“We hope that they will join the president,— Rep. Sheila Jackson Lee (D-Texas) said.

“Our cause, our civil rights issue, is a public option,— she said. “We will throw ourselves in front of a running train for this once-in-a-lifetime opportunity.—

[IMGCAP(1)]The liberals, who dominate the House Democratic Caucus, argued that the insurance companies have been a large part of the problem of inadequate and costly health care and must have a public competitor to keep them honest.

But while there is strong momentum in the House for the public option, the issue has become the biggest stumbling block for Senators trying to craft a bipartisan bill.

Democrats and Republicans alike cautioned their House counterparts Wednesday against drawing lines in the sand — despite the fact that many in their own chamber have made similar pronouncements on the government-run insurance option.

“Our own leader, [Senate Majority Leader] Harry Reid [D-Nev.] has urged us as Democrats not to lay down those markers, and not to say it’s got to be this or that, otherwise I won’t support— a bill, Sen. Tom Carper (D-Del.) said. “He’s urged us to keep an open mind, to let the process work, let everybody raise their concerns and provide their input. But he said: Please don’t back yourself into a corner.’—

“That’s good advice for Democrats, and Republicans, in the Senate and the House,— Carper said.

For Republicans, the debate over whether to include a government-run insurance option trumps all others, even the possibility that a reform bill could exceed $1 trillion over 10 years, who would pay for it, or the role employers would play.

Democrats believe implementation of a public plan will bring fairness and affordability to the system. But Republicans argue it would undercut the private insurance market and ultimately lead to a single-payer system run by the government.

That’s, of course, something many liberals would be happy to see. They contend they’ve already compromised since most of them would prefer a single-payer, government-run universal health care system.

Sen. John Thune (R-S.D.) warned that even if a bipartisan deal is reached in the Senate, it could die in any conference report if the House insists on a public option.

“It’s going to make it problematic for them probably to pass something that doesn’t have a public plan option included. But, I think it’s also going to be equally problematic to say that you passed anything with bipartisan support that includes it, because the Republicans’ bright red line on this is no government takeover. And, that to us is what the, quote, public-plan option — what we call the government plan — represents,— Thune said.

Meanwhile, two Senate committees continued their work Wednesday on health care bills, with the goal of merging them into a single measure that can clear the chamber by the first week of August.

Finance members were hunkered down in private, bipartisan meetings while the Health, Education, Labor and Pensions Committee spent another day marking up its bill.

However, Sen. Chris Dodd (D-Conn.), who is managing the HELP panel in the absence of Chairman Edward Kennedy (D-Mass.), conceded Wednesday the markup will likely extend into next month.

Finance had already postponed its markup until after the July Fourth recess, giving the two panels more pressure to complete their work, merge their bills and get Senate approval by August.

Still, Finance Chairman Max Baucus (D-Mont.) said Wednesday that his panel is making good progress toward a compromise: “It’s a long road because health care reform is very complex.—