Who will Elizabeth Warren endorse?

The most sought after endorsement right now is Elizabeth Warren’s, who folded her Democratic presidential bid Thursday not making a choice between Bernie Sanders and Joe Biden, leaving Illinois supporters — who are already early voting — no guidance for now.

Warren’s backers do not automatically flow into one camp or the other — this one is more complex. Warren has enormous leverage and can bring her supporters with her when she decides. First she — and they — will need to see if Sanders or Biden will be advancing any of her big ideas.

When ex-South Bend Mayor Peter Buttigieg, Sen. Amy Klobuchar, D-Minn., and former New York Mayor Michael Bloomberg ended their campaigns, their moderate views made it easy — even obvious — for them to swiftly endorse Biden.

Three top Illinois Warren backers — Rep. Jan Schakowsky, D-Ill., state Treasurer Mike Frerichs and former state Rep. Dan Biss — are weighing their options for now.

Warren appealed to the progressive space in the Democratic party also occupied by Sanders followers. During much of the campaign they had an informal peace pact.

The bad blood developed after Warren alleged Sanders told her a woman could not win the presidency. Sanders said he was falsely accused. She used it in the last debate before the Iowa caucuses.

Frerichs was Warren’s earliest public supporter in the state, endorsing her last July. Going forward, “Today I’m not doing anything in terms of other endorsements. I think she set an example that you could advocate passionately for progressive ideas without being divisive. And I think it is important that at the end of the day we unify behind a candidate that can defeat Donald Trump.”

As for deciding between Sanders, the Vermont Independent — who is not a member of the Democratic Party — and Biden, the former vice president, Frerichs said, “I will listen to what Sen. Warren has to say, but I will listen to friends, allies, supporters here in Illinois before I make a decision.”

Biss, who ran for governor in the 2018 Democratic primary, endorsed Warren last August. On Thursday he told me, “I think she has considered every decision she has made in her political career carefully to how she can best advance the political agenda she is committed to.”

Biss early voted on Tuesday for Warren. “It felt great. And that’s that.” Whether he might endorse another candidate, he said, “I haven’t given much thought to that yet.”

Schakowsky is “still weighing her decision,” her political director, Ben Head, told me.

WHITHER DURBIN?

An issue for Democratic voters is whether Sanders — a democratic socialist — at the top of the ticket will make it harder for swing district congressional candidates to survive. Sanders may also prove an obstacle to Democrats picking up four seats to flip the Senate — with only three needed if the president is a Democrat.

The Sanders argument is that he — being a movement candidate — has the ability to bring out more Democratic voters so not to worry.

So far, Sen. Dick Durbin, D-Ill., has not endorsed. He is up for reelection in 2020 and faces no strong primary or general election competition. My analysis here is Durbin — if he does not endorse — preserves his ability to unify the factions after the Democrats pick their nominee.

Freshman Rep. Sean Casten, D-Ill. — who flipped a Republican district in 2018 (OK, one Hillary Clinton won in 2016 ) came out for Biden on Thursday. He said in a statement, “As a freshman member I am keenly aware of the power of strong, diverse coalitions. For that reason, I am proud to announce my support for Joe Biden. Joe has the empathy and the heart to unite our party, our country — and he has experience and the tenacity to get it done.”

The other vulnerable freshman, Rep. Lauren Underwood, D-Ill., — in a district Trump won in 2016 — so far is staying out of presidential politics.

JILL BIDEN IN CHICAGO AREA FRIDAY

Former second lady Jill Biden hits Glencoe and Chicago on Friday. She headlines a fundraiser in the northern suburb for her husband in the morning and then heads over to Rosemont to speak to the Illinois Education Association Representative Assembly. Biden is in Chicago on March 13 for a fundraiser and possible other activities.