Harry Reid won’t run again. Meet the three senators who will lead Democrats next.

UPDATED at 12:20 p.m.

Senate Minority Leader Harry Reid’s announcement that he will not seek reelection in Nevada sent shockwaves through the political world Friday and set up a potentially intense, intra-Capitol battle to determine the next Democratic leader that Reid moved quickly to forestall.

Reid had repeatedly assured other senators, staff and reporters that he would seek reelection in 2016, even after an early January accident forced the senator to have multiple eye surgeries this year. Now, with his apparent change of heart, Senate Democrats could face two parallel campaigns: the fight nationwide to win back the majority—and the fight here in Washington to choose a new face to lead their party.

Reid told the Washington Post Friday morning that Sen. Chuck Schumer of New York “should be able to succeed me.” After his years of service to Reid as the party’s messaging lieutenant and conference vice chairman, Schumer has been the favorite. The Post reported Reid and Minority Whip Dick Durbin of Illinois had a phone call in which Durbin said would “stand aside” for the New York Democrat, though neither office would comment further. Durbin then said he would back Schumer’s bid for leader while also running again to keep his post as whip. Meanwhile, No. 4 Democrat Patty Murray of Washington was on a transcontinental flight back to her home state.

Congressional leadership elections turn on lawmakers’ clout and standing with colleagues, their political and policy track records and the message they want to send with their election. In this regard, Democrats have a real choice when it comes to picking a successor to Reid. Schumer is certainly one candidate for the job, but Reid’s statements Monday might not necessarily keep others out of the race. Durbin has a role in the party’s leadership and perhaps wants to hold on to his No. 2 spot, but Murray also could launch a challenging bid for either top spot if she chooses. Her office would not comment on her intentions.

Each of these three leaders brings different strengths and weaknesses to the table and certainly will play different roles without Reid, regardless of who ends up being top dog:

Schumer, the pundits’ presumptive favorite: Schumer has served in the Senate since 1999 and has proven to be one of the party’s top tacticians and fundraisers. He was chairman of the Democratic Senatorial Campaign Committee from 2005 to 2009, meaning that he helped usher in a wave of new Democrats to the Senate. Traditionally, helping to elect senators brings a natural base of allies to the launch of a leadership bid, because they feel in part beholden to your efforts. The problem for Schumer, however, is that many of the Democrats who won in 2008 under his DSCC stewardship went on to loose re-election in 2014.

Schumer has all the right qualities to be an excellent minority leader: he is a tenacious attack dog for the Democratic position. His official messaging role for Senate Democrats, created by Reid in 2011 after a resounding midterm defeat for the party, has been heralded largely as a success. The Schumer-Reid-led Democratic Policy and Communications Center (DPCC) has unified the party around middle-class, economic and women’s rights issues. The Schumer DPCC also has produced prominent alumni in Katie Beirne Fallon, now the top White House legislative liaison, and Brian Fallon, recently named as a top Hillary Clinton campaign spokesperson.

But the question Democrats privately have is over Schumer concerns his policy chops. Schumer would argue that his 2013 work on bipartisan immigration reform legislation, which passed the Senate but never got a vote in the House, proves he can lead on bills as well as at press conferences. His legislative record on non-parochial issues, however, is thinner than those of other potential leaders—his position within the party has oriented him more toward attacking Republicans than proactively negotiating and legislating for Democrats. His big personality means that of the three potential candidates, he also likely has the most opponents within the caucus, but that does not mean he won’t corral the support to win—especially with Reid’s backing.

Durbin, the loyalist: Durbin has been a senator since 1997, and like Schumer, he came to the upper chamber after a significant stint in the U.S. House. Durbin has been a tried-and-true No. 2 to Reid since Reid assumed the position of Democratic leader in 2007. Reid, a former whip himself, chose Durbin to run with him on the leadership ticket because Durbin is reliable, generally well-liked and trustworthy. But Reid also was more of a micromanaging leader, keeping many of the tools of the whip to himself when he ascended to majority leader out of his own self-interest to build clout. And the same qualities that led Reid to choose Durbin to be his No. 2 also have led Durbin to be less aggressive than Schumer, at least outwardly, about his leadership ambitions.

It had been rumored that Durbin would retire rather than seek reelection in 2014. He changed his mind, in part, because he assumed a top role on the powerful Appropriations Committee, and is tasked with budgeting the nation’s defense spending. But the tension between Schumer World and Durbin World is long simmering: despite the fact that the two men lived together in a house on Capitol Hill for decades, both faced questions about whether they would seek to replace Reid as far back as during in the 2010 election, when Reid appeared to be on the ropes in Nevada. Schumer aides and Durbin aides have frequently expressed their disdain for each other to others within the party and to reporters. And Durbin’s staffers were less aggressive in building their presence within the conference, even as Schumer’s staff kicked into overdrive, especially with their new Reid-granted power at the DPCC in 2011.

Durbin, the downstate Democrat to Schumer’s city fighter, has been an assiduous worker, running the floor for the party for almost a decade. His position on appropriations and legislative work big and small leaves him with a stronger policy portfolio than Schumer; he stewarded a revamp of the nation’s food safety laws in 2010 and has worked in almost every major policy negotiating group in his tenure as whip. But his fundraising ties to other members are not as deep as Schumer’s.

Murray, the darkhorse: Murray would be the least discussed but perhaps most interesting challenger to Schumer, should she choose to pursue a leadership bid. She’s been in the Senate since 1993, and it’s about time to hang up the “mom in tennis shoes” mantra she ran on — and that gets consistently dropped in each profile about her — because she is as fierce a competitor as any in politics. Murray has taken every powerful position no other Democratic senator wanted, from the DSCC chairmanship in 2012, when everyone thought Democrats were going to lose the Senate (but did not), to the head of a doomed-to-fail bipartisan, bicameral deficit reduction group that attempted to find nearly $2 trillion in spending cuts.

She has been a top advocate for women’s issues throughout her leadership tenure. In the spring of 2011, when other top Democrats mulled letting Republicans slash Planned Parenthood funding in order to avoid a government shutdown, Murray refused, and instead launched a sustained press campaign to successfully retain federal support . She often leads groups of other female lawmakers in press conferences and bills that affect women, from health care to equal pay.

Unlike Schumer’s class of freshmen, the members she brought into the Senate in 2012 are still in Congress. And when speculation swirled in 2010 over who might replace Reid in the event of his loss, she and her staff stayed above the Schumer-Durbin bickering fray. Of the four top Democrats—Reid, Durbin, Schumer and her—she is the one who has the best relationships overall with all the others and the fewest enemies among rank-and-file members.

There’s also a big messaging upside for the party should she run and win the leadership post: Murray would be the first female Senate Democratic leader. Leaders are the faces of the party, for better or worse. And in a political world where a woman could be at the top of the presidential ticket and Nancy Pelosi runs the House Democratic caucus, Democrats could continue to push the message that they are the party that puts women in charge and listens best to their concerns. Murray certainly would get the backing of groups like Emily’s List if she pursued a run. Durbin, to whom she is close, could also decide that he does not want to run but would prefer to throw his voting bloc behind her.

Murray is not as flashy as Schumer, and while that’s a weakness for a minority leader, she’s has worked in a bipartisan fashion with a litany of Republicans, from House Ways and Means Committee Chairman Paul Ryan to Financial Services Committee Chairman Jeb Hensarling. And while she’s not nakedly ambitious, she also seems to have designs for something bigger than party secretary.