Washington ? With time growing short, Senate Democratic liberals are seeking expansion of two large federal programs, Medicare and Medicaid, as part of a compromise that drops a government insurance option from health care legislation sought by President Barack Obama, several lawmakers said Monday.

Under the potential trade-off with party moderates, near-retirees beginning at age 55 or 60 who lack affordable insurance would be permitted to purchase coverage under Medicare, which generally provides medical care beginning at 65. Medicaid, the federal-state health care program for the poor, would be open to all comers up to 150 percent of poverty, or slightly over $33,000 for a family of four.

The compromise under discussion also envisions private insurance companies selling national, nonprofit plans, to be overseen by a federal agency, an alternative to a longstanding call by liberals for the government to sell insurance as a means of forcing competition on the industry.

“It’s one of those kind of things in the middle that doesn’t make everybody very happy but that’s our compromise,” Sen. Tom Harkin, D-Iowa, said after talks ended for the day. “It’s something I’m going to probably have to live with.”

Harkin also said Majority Leader Harry Reid had imposed a deadline of today on the talks as he tries to complete work on the sweeping legislation in the next few weeks.

While Harkin and others spoke with optimism, there were few details available. It was not immediately clear, for example, what the legislation would provide if no insurance company agreed to sell a nationwide nonprofit plan.

Senators and aides said the changes have been discussed extensively in recent days as a small group of moderate and liberal Democrats search for a middle ground to assure passage of the bill atop Obama’s domestic agenda.

Additionally, the president met privately at the White House over the weekend with Sen. Olympia Snowe of Maine, who supported a Democratic-drafted bill in the Senate Finance Committee earlier this year but has spoken out against the legislation pending on the floor. Senate Democrats also have been in contact with Snowe in recent days.

Given the complexities of the two programs and the White House’s goal of passing legislation by year’s end, it wasn’t clear whether the negotiations would ultimately bear fruit, or merely prove to be a last stab by liberals at salvaging some concessions in a months-long debate over a so-called public option.

As the search for compromise intensifies, several Democrats also said a plan by Sen. Maria Cantwell, D-Wash., was receiving new interest as a means of injecting additional competition into the insurance system. It gives states an option to negotiate with private industry to provide less expensive group coverage for lower income residents. Currently, the bill allows that for any state’s residents up to twice the federal poverty level, about $44,000 for a family of four, but that could be raised if negotiators decide they want to do so.