With time running out and Republicans escalating their attacks on Democrats’ health care plans, Senate Majority Leader Harry Reid (D-Nev.) and Sen. Charles Schumer (D-N.Y.) launched a last round of talks with fence-sitting Sen. Ben Nelson (D-Neb.) Wednesday afternoon that culminated in a deal to move Reid’s legislation, Democratic leadership aides said Saturday.

According to these aides, a series of calls and preliminary meetings among the trio of lawmakers laid the groundwork for the final round of talks, which ultimately expanded to include Sen. Barbara Boxer (D-Calif.), White House Deputy Chief of Staff Jim Messina and President Barack Obama’s senior adviser Pete Rouse.

Initially setting aside the tricky issue of abortion, Nelson at a 6 p.m. Wednesday meeting provided Reid and Schumer with a list of non-abortion “fixes— he wanted in the bill, including insurance tax exemption for nonprofit insurers, exemption for Medigap plan providers, indexing of flexible spending account limits, and an opt-out from Medicaid for Nebraska.

Schumer and Reid took the list to Messina and Rouse, and together they worked through a series of options for addressing Nelson’s demands as well as the potential budget scoring implications of those options. According to the leadership aides, it was out of those meetings that Reid ultimately decided to permanently put Nebraska’s Medicaid costs on the federal government’s tab, rather than give the state an opt-out.

Reid then brought Nelson back into the talks Friday morning, and along with Schumer, Rouse and Messina, they worked out a deal on those provisions by noon.

After a brief lunch in Reid’s office of tuna and turkey wraps, the group began the difficult work of tackling the abortion issue. Nelson, an anti-abortion lawmaker, had concerns that the Senate bill would undercut a long-standing bar on federally funded abortions known as the Hyde Amendment. Although Nelson had originally wanted the Senate bill to include language similar to provisions inserted into the House bill by Rep. Bart Stupak (D-Mich.), that language had been strenuously opposed by Senate liberals.

By 4:30 p.m. Friday, the group had made enough progress to bring in Boxer, who was tapped as the standard-bearer for abortion rights Members in the talks.

With Nelson and his staff ensconced in Reid’s own office and Boxer’s camp set up in the office of Reid’s chief of staff, Gary Myrick, Reid and Schumer began a round of shuttle diplomacy, trading language between the two sides as they whittled down the differences.

With a deal in sight, the lawmakers decided to take a break Friday evening, with Nelson expected to return to Reid’s office by 8:30 p.m. But as 8:30 turned into 8:45 and then 9 p.m. and Nelson still had not turned up, Rouse and Messina departed briefly to attend a White House “watch party— of the NCAA Division 1 championship football game between Villanova and Messina’s alma mater, the Montana Grizzlies.

Reid and Schumer, meanwhile, were left to worry with no word of their moderate colleague’s whereabouts.

By 9:15 p.m. Friday, Reid and Schumer were increasingly concerned the deal was unraveling. Nelson, who had left to discuss the issue with anti-abortion-rights organizations, was more than an hour late.

Finally at 9:30 p.m., Nelson returned to Reid’s office, and the negotiators spent the next hour hammering out the final details of the agreement. Although Nelson said he would withhold a formal agreement to the deal until it was included in Reid’s written manager’s amendment to his bill Saturday morning, he assured Reid he would back the bill, hugging both Reid and Schumer before leaving.

After Nelson’s departure, Boxer came to Reid’s office. At approximately 10:30 p.m., Obama called from Air Force One, and Reid put the call on speaker phone to allow Obama to congratulate the trio for their work.

Emily Pierce contributed to this report.