WASHINGTON — Earlier this month, Sen. Susan Collins, dispirited, sat watching her colleagues on the Senate floor stake out opposing positions over funding the government. She decided she’d had enough.

“Each side was lobbing partisan grenades at the other side, despite the fact that we had a really serious problem confronting us,” the Maine Repuiblican said in an interview this week.

The plan that Collins, a Republican, later proposed helped spur momentum for talks to end the government shutdown and lift the nation’s borrowing limit. Two days before the government is expected to run out of money to pay its bills, Senate leaders Harry Reid, a Nevada Democrat, and Mitch McConnell, a Kentucky Republican, are seeking support for an emerging bipartisan agreement. A final deal proved elusive as House Republicans floated a proposal that Reid rejected as unacceptable.

Collins’s profile in the standoff is part of a bigger trend of women lawmakers, now serving in record numbers, expanding their portfolios to fiscal and other issues transcending gender. Patty Murray, who in 2011 co-chaired a supercommittee charged with reaching a comprehensive deficit-cutting deal, went on to become the first woman to head the Senate Budget Committee. Sen. Barbara Mikulski, D-Md., is the first female to lead the Appropriations Committee.

Collins’ approach to the current budget debate, which she outlined Oct. 5 on the Senate floor, picked up steam after she won support from two other lawmakers, Republicans Kelly Ayotte of New Hampshire and Lisa Murkowski of Alaska. Soon, Democrats Heidi Heitkamp of North Dakota and Jeanne Shaheen of New Hampshire joined the talks. Behind the scenes, Collins traded phone calls and emails with Murray, a Washington Democrat.

“I do think it was significant that, in this bipartisan group of members that I put together, women were disproportionately represented,” said Collins, 60, who was first elected to the Senate in 1996.

Her plan would limit federal spending to $967 billion, set a mid-January deadline for longer-term budget talks, delay a medical-device tax that’s intended to help fund President Barack Obama’s health-care program, and require the administration to verify income levels for getting health-insurance subsidies.

“Her effort helped provide the momentum to where we are today,” Heitkamp said in an interview. “It was with an enormous interest in making sure the public was represented.” Shaheen called it “a good jumpstart to try and get some agreement.”

The Senate plan, and a separate one being discussed in the House, would both fund the government through Jan. 15, 2014, and suspend the debt limit until Feb. 7. A House vote as soon as tonight would test whether Republicans are willing to raise borrowing authority and end the shutdown without major changes to the 2010 Patient Protection and Affordable Care Act.

Earlier this year, members of Collins’ group, which meets about once a month over dinner, joined to press a series of bills aimed at addressing the problem of sexual assaults in the military. Now, they’re moving into wider issues.

“This is saying we’re stepping out of the pink ghetto,” said Jean Schroedel, an expert on women in politics and leadership at Claremont Graduate University in California.

“The folks playing chicken games need to recognize that there now is a real group that has bonded and isn’t into playing chicken games,” said Schroedel. “This is an important phenomenon, and it’s like sanity, for crying out loud.”

Collins’s readiness to deal with Democrats is reminiscent of another Republican from Maine, a lightly populated coastal state that’s partial to politicians willing to cross the aisle. Prior to her retirement, Sen. Olympia Snowe often worked with Democrats even as Congress became increasingly polarized along partisan lines.

While Maine’s Republican governor, Paul LePage, is aligned with the limited-government tea party movement, its legislature is controlled by Democrats and the other Senate seat is held by independent Angus King, who caucuses with Democrats.

“It’s the capital of American bipartisanship,” said Ross Baker, a congressional expert at Rutgers University in New Brunswick, N.J.

Politics in America, a congressional almanac, describes Collins as “the most moderate member of her party.” In 2004, she teamed up with Joe Lieberman of Connecticut, a Democrat who later turned independent, to rewrite intelligence laws. She has led bipartisan investigations into the federal response to Hurricane Katrina under former Republican President George W. Bush and the 2012 attack on a U.S. diplomatic mission in Libya.

“Susan Collins is a gang of one,” said Baker. “She is the person the Democrats turn to almost immediately when they want to try to get bipartisan support on legislation.”

Even though discussions are now in the hands of the leadership, Collins says her efforts helped provide the “elements” of a deal. “The leaders are going to take it from here,” she said.

Monday, after meeting with McConnell in his office, Republican lawmakers gave a nod to Collins.

“I think we’re all working around the same framework,” said Sen. Mike Johanns., R-Neb “I thank Susan for your efforts.”

With assistance from Peter Cook in Washington.