— The Associated Press

WASHINGTON — The White House signaled Thursday that an aggressive, all-Democratic strategy for overhauling the nation’s health care system remains a serious option, even as President Barack Obama invites Republicans to next week’s televised summit to seek possible compromises.

The administration’s stance could set the stage for a political showdown, with Democrats struggling to enact the president’s top domestic priority and Republicans trying to block what many conservatives see as government overreach.

A senior administration official said Democratic congressional leaders have nearly finished efforts to reconcile two health bills, which the House and Senate passed separately last year with practically no Republican help. Obama will use their legislation, aimed at expanding coverage to some 30 million people and requiring most Americans to carry insurance, as the basis for a proposal that the White House will post online by Monday, three days before the Feb. 25 summit, said the official.

The official spoke on condition of anonymity to discuss private negotiations.

Obama says he is open to Republican ideas for changing the health care system. But many Democrats seriously doubt GOP leaders will support compromises that could draw enough lawmakers from both parties to create a bipartisan majority.

If next week’s meeting does not break the logjam, congressional Democrats will face a tough choice. They can pass a highly diluted health care bill or nothing at all, which would send them into the November elections with a high-profile failure despite their control of Congress and the White House.

Or they can use an assertive and contentious tactic, known as reconciliation, to pass a far-reaching health care bill in the Senate without having to face GOP delaying tactics. Democrats lost their ability to block filibusters when Massachusetts Republican Scott Brown won a Senate seat last month.

Both parties have used reconciliation rules in the past. But Republicans have practically dared Democrats to do so on health care, citing polls showing significant opposition to the legislation.

It’s unclear whether the House or Senate can muster the necessary votes. Democrats, who now hold 255 of the House’s 435 seats, drew only one GOP ally when the House passed its health care bill, 220-215, last November. Since then, one Democrat who voted for the bill has resigned, one has died and a third plans to leave office Feb. 28. Moreover, changes meant to meet Senate demands could peel away enough liberals on one end, and party centrists on the other, to cause the revised bill to fail.

In the Senate, Democrats control 59 seats, and reconciliation rules require only a simple majority. But several Democratic senators have expressed discomfort or outright opposition to using the rules to thwart filibusters on health care.

Health and Human Services Secretary Kathleen Sebelius said Thursday that Obama plans to have a health care proposal that ”will take some of the best ideas and put them into a framework” ahead of the Feb. 25 summit. The White House has invited Republicans to bring their own proposals, but GOP leaders have treated the event warily at best.

House Republican leader John Boehner of Ohio said Thursday, ”A productive, bipartisan conversation on health care starts with a clean sheet of paper.” His office labeled next week’s meeting the ”summit of all fears.”

But at least one moderate Republican was optimistic about the session.

Sen. Susan Collins of Maine said if the summit succeeds, a bipartisan bill could be put together and passed within six weeks. ”My advice to our Republican leadership is we should view this as a good faith effort and go in there with a consensus list of provisions that we could support and that would make a difference,” she said in an interview.