If you only casually follow politics, you probably don’t know much about Senator Patty Murray. She's rarely on TV or in the headlines. She’s not inclined to tear into her Republican colleagues or give floor speeches that go viral, like Senator Elizabeth Warren does. But Murray has become one of the most important dealmakers in the Democratic Party. 

In just the past month, she has teamed up with Republican Senator Lamar Alexander to reform No Child Left Behind and worked with Senate Majority Whip John Cornyn to pass a stalled human trafficking bill. She’s joined with Representative Paul Ryan to promote evidence-based policymaking, having developed a trusting relationship with him after the two reached a budget deal in 2013.

Yet Murray, 64, isn’t a red-state Democrat maligned by liberals. Currently the ranking member of the Senate Health, Education, Labor and Pensions (HELP) Committee, she champions progressive issues like paid sick leave and equal pay. This week, she’ll introduce legislation to raise the minimum wage to $12 per hour by 2020.

So how has she managed to forge these bipartisan agreements?

She's certainly accrued power over 22 years in the chamber, during which time she has run the Democratic Senatorial Campaign Committee, chaired both the Senate Budget Committee and Senate Veterans' Affairs Committee, and ascended to the number four position in the Democratic caucus. And then there's her demeanor. Murray became Washington state's first female senator after a political opponent dubbed her "just a mom in tennis shoes" (she embraced the description), and has earned a reputation as a nice, no-nonsense colleague.

But there's more to her success than that, and it may hold the key to bridging the partisan divides that have paralyzed Washington.

The gridlock on Capitol Hill in recent years has led some pundits to bemoan the lack of collegiality in Congress and wax nostalgic about the days when senators Ted Kennedy and Orrin Hatch would supposedly cut deals in cigar-filled backrooms. But back then, there was significant ideological overlap between the parties. That's not true today. A growing body of research confirms that polarization has not been exaggerated; it's the prime cause of diminished dealmaking. While some politicians have used this polarization to rail against the opposing party and raise their political profile, others have focused instead on finding the few areas ripe for compromise. Perhaps no one in the Democratic Party has been better at that than Patty Murray.

At the end of February, legislation to protect human trafficking victims passed the Senate Judiciary Committee and seemed destined for the president’s desk. But when it came to the floor in early March, Senate Democrats filibustered it, objecting to a provision that would prevent money in a new victims' fund from being used for abortions. This provision, Democrats argued, was an expansion of the so-called Hyde Amendment, a provion that prohibits the use of taxpayer dollars for abortions and is commonly attached as a rider to bills. (The fund comes from fines levied against trafficking offenders.) In retaliation, Senate Majority Leader Mitch McConnell refused to allow a vote on Obama’s nominee to replace Attorney General Eric Holder, Loretta Lynch.

The gridlock lasted until last week, when Murray and Cornyn reached a deal. The fund would be split in two: Money from the fines would go toward non–health care services like legal aid (not subject to the Hyde Amendment), and federal funding (subject to the Hyde Amendment) would cover health care services. The bill passed 99-0 last Wednesday. The following day, the Senate confirmed Lynch.

What allowed this compromise to happen? “We needed to show the Republicans five times that they weren’t going to get it ‘my way or the highway,’” Murray said in an interview in her office last week. “We had the votes in our caucus and we stood firm on our principles. And we said we’re not going to accept this bill that sets a new precedent for how Hyde is used on non-taxpayer dollars.” She added, “It wasn’t until we showed them that we really aren’t moving that I got a call from the other side to ask me to sit down and see if we could work out a path forward.”

Setting red lines—and understanding her negotiating partner’s red lines—is one of the foundations of Murray’s strategy, which she used to reach a budget deal with Paul Ryan.

“From day one, [Murray and Ryan] weren’t going to spend months attacking what the other wasn’t going to budge on,” a Republican aide said. “They had a cordial agreement. 'I’m not going to touch this. I don’t think you’re going to touch that. Let’s find the areas where we can find common ground.' That was the driving principle.”

“When I worked with Paul Ryan, I needed to know what was important to him,” Murray said. “What did he want at the end of the day? What story did he need to tell to personally feel successful?” As Ryan recently told the Associated Press, "She's very tough in defense of her policy and principles. But she's nice about it."

This same approach has helped her build relationships with Republican legislators on other issues. Her most impressive accomplishment may be her work with Lamar Alexander to reform No Child Left Behind (NCLB). Legislators tried to fix NCLB, which was passed in 2002 and is widely viewed as a failed law, in 2007, 2011, 2012 and 2013. But all those attempts failed. When Alexander announced he would take another chance at rewriting it, few people had high hopes for success. But the Alexander-Murray duo have proven the doubters wrong so far.

What's more, Murray didn't have to capitulate to reach an agreement. “[Compromise] doesn’t mean that you come in here and say, ‘Lamar, I’ll do whatever you say. I want a bill out of here and you write it and I compromised because I’m with you,’” Murray said. “That’s not compromise from either side.”

The final deal has yet to receive a vote on the Senate floor, but its odds of passage look good. It passed the Senate HELP Committee 19-0, receiving support from senators as ideologically diverse as Rand Paul and Elizabeth Warren. Teachers unions support it, too. “Patty Murray’s skill in working with Sen. Alexander to move the NCLB overhaul through the committee in a truly bipartisan fashion was masterful,” Randi Weingarten, the president of the American Federation of Teachers, wrote in an email.

Murray, a petite blonde, has cultivated a low-key image that often makes these negotiations easier. She isn't slinging mud on the Sunday shows, although she enjoys watching them. This helps build trust between Murray and her Republican counterparts.

“I’ve enjoyed working with Patty,” Alexander said. “She likes to get a result. I like senators who are here not just to make speeches but to get a result and she’s one of them.” Republicans know that when Murray negotiates, she's speaking for the party.

"Her strong, steady and principled leadership has earned her not just my confidence," Senate Minority Leader Harry Reid said through a spokersperson, "but also the trust and respect of the entire Senate Democratic caucus."

Senator Sherrod Brown put it simply: “She’s just good.”

But is “being good” enough to overcome partisan divides in Washington? In most circumstances, it’s not. Republicans and Democrats can’t agree because there is often no common ground acceptable to both sides. Polarization, not a lack of personal relationships across the aisle, is the root cause of gridlock. But Patty Murray’s negotiating strategy demonstrates how legislators can capitalize on moments when the two parties’ political incentives align.

For instance, if Paul Ryan did not believe a budget deal was in the best political interests of him and his party, he probably wouldn't have negotiated it. But Murray and Ryan’s negotiations came just a few months after the government shutdown, which caused the Republican Party's approval ratings to plummet. The GOP couldn't afford another shutdown before the midterm elections, giving Ryan every incentive to find a deal.

This is partially why Congress has become more productive of late. Senate Democrats have an incentive to work with Republicans on a bill empowering Congress to vote on any final deal with Iran over its nuclear program. If Democrats filibustered the GOP legislation, Obama could complete the deal without any Congressional action. Republicans, due to their opposition to Eric Holder, had an incentive to confirm Loretta Lynch and thus negotiated over the anti-human trafficking bill. In past years, Republican leadership would never have accepted legislation to end the need for a “doc fix” bill, which had required annual action to prevent huge cuts to Medicare providers (and added hundreds of billions to the defict). But now in the majority, McConnell and company have an incentive to show that the Republican Party can govern. In other areas, like trade and possibly patent reform, Republican lawmakers can work with centrist Democrats to pass legislation that Harry Reid blocked as senate majority leader.

When Murray talks about her deal-making, though, she doesn’t talk about political incentives aligning. She talks about people and trust.

“I think it’s a lot to do with people and why they come here and want to accomplish,” she said. “One of the things that Paul Ryan and I really focused on is that we had forgotten how to applaud compromise here.”

Murray's relationship with Ryan, like her relationship with Lamar Alexander, allowed her to find middle ground—because their political incentives aligned. But often, in Washington, there's no such incentive. Think back to the so-called supercommittee in 2011 that was tasked with reducing the deficit more than $1 trillion. Six Democrats and six Republicans spent many months searching for a compromise, knowing that failure would result in across-the-board spending cuts that neither side wanted. But that looming threat wasn't enough. The supercommittee failed. One of the Democrats on the committee? Patty Murray. Even the Democrats' star dealmaker couldn't bridge that political divide.