BUSY DAY IN THE SENATE…. The Senate debate over health care reform formally began six days ago, and immediately got bogged down. Progress came in fits and starts, but movement came at a snail’s pace.

This upcoming week is likely to be more interesting, starting today at 2 p.m. (ET).

With the Senate clashing over health care legislation through the weekend, President Obama will head to Capitol Hill on Sunday afternoon to meet with the Democratic caucus in a session that aides at both ends of Pennsylvania Avenue said was designed to galvanize lawmakers, even as they remain internally divided over many important issues.

The visit will come on the heels of several key meetings among senators yesterday. What was expected to be a fairly quiet day was anything but. Groups of liberal and conservative Democratic senators met in the morning to negotiate on the public option, followed by breakout meetings between the contingents in the afternoon, concluding with another joint meeting late yesterday. While the usual suspects were involved in the discussions, Sen. Chuck Schumer (D-N.Y.) acted as an intermediary. Sen. Joe Lieberman (I-Conn.) was invited to the talks, but did not attend. It’s unclear why.

Worth noting, of course, is Sen. Olympia Snowe’s (R-Maine) role — she sat down with the center-right Dems to hear their thoughts on the matter. It was her first participation in bipartisan talks since the Gang of Six effort failed in September. (Maine’s Susan Collins did not participate, but she is signaling a new-found interest in playing a constructive role.)

Details are sketchy, but the newest proposal is being referred to as the “OPM Plan,” in reference to the Office of Personnel Management. Sen. Blanche Lincoln (D-Ark.) appears to be its biggest champion.

There appeared to be serious consideration of a new proposal on the table: a national health plan similar to the Federal Employee Health Benefits Plan, which provides insurance to members of Congress and federal workers. It would be administered by the Office of Personnel Management, which oversees the federal plan, and all of the insurance options would be not-for-profit. […]

Details on the latest proposal for the public option were limited late Saturday. Brown described it as a take-off of the Federal Employee Health Benefits Plan. With the Office of Personnel Management as the administrator, the program would be separate from the Department of Health and Human Services, which regulates the insurance marketplace.

“It would be a national, not-for-profit,” Brown said. “(The Office of Personnel Management) would administer it. It would be any number of national not-for-profits that would compete nationally and they would take the place – more conservative members hope – of the public option. They would be in states and be running a kind of lookalike to a public option.”

The nonprofit insurance companies would “go to OPM and say I want to compete and then you show them you’ve got standing to compete,” Brown said.

Existing insurance companies could participate as long as their plan is not-for-profit, he said.

Lincoln said she, as well as Snowe and Majority Whip Dick Durbin (D-Ill.), has advocated a similar proposal in the past for small businesses. The Office of Personnel Management has been effective in negotiating affordable premiums and generous benefits in the Federal Employee Health Benefits Plan — and could presumably do the same under this expanded program, Lincoln said.

After the president’s visit at 2 p.m., the discussions are expected to begin again at 4, and extend into the evening. Rumor has it, the senators hope to have a deal struck on the public option within the next couple of days.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.