Democrats won the Senate. Now Chris Van Hollen wants Chuck Schumer’s job, and the Iran war is his argument

Less than a fortnight after Democrats won control of the US Senate, the party is fighting over who should run it.

Chris Van Hollen, the 67-year-old senator from Maryland, announced on Thursday (US time) that he will challenge Chuck Schumer, 75, for leader of the Senate Democrats. Schumer has led the caucus since 2017. No one has contested the job since 1994.

Schumer’s answer was short. “I have the votes to continue serving as Democratic Leader,” he said, pointing to what he called “55 seats and counting”.

Van Hollen calls himself the underdog, but says more than 10 Democratic senators are already with him and that the race is “very much in flux”.

Why challenge a leader who just won?

Van Hollen’s case is that the election gave Democrats a chance, not a blank cheque. “You can’t earn that trust with old leadership,” he said.

His sharpest point is about money. The US government’s funding runs out on 11 December, and Van Hollen says Democrats should use that deadline to force the Trump administration to end the war with Iran. He has also criticised Schumer for backing candidates in open Democratic primaries, naming two senators-elect who beat the leadership’s favoured picks: Abdul El-Sayed in Michigan and Peggy Flanagan in Minnesota. Both have since praised Van Hollen.

He is also one of the Senate’s most outspoken Democratic critics of Israel, and the contest is expected to lay bare the party’s divide over Israel.

Who is backing whom?

Senator Bernie Sanders has endorsed Van Hollen, saying the public “voted for change”. Outside the Senate, progressive groups including Indivisible, MoveOn, the Working Families Party and the Sunrise Movement have lined up against Schumer, and the 600,000-member International Association of Machinists has written asking him to step aside.

Schumer has the senators who matter most for now. Jacky Rosen of Nevada has endorsed him, Kirsten Gillibrand, who ran the party’s Senate campaign, has defended him, and Ruben Gallego of Arizona put it in baseball terms: when a manager takes you to the World Series, “you give them another contract”. Elissa Slotkin of Michigan says she will not back Schumer until she sees a concrete plan, and at least one Democrat elected this month has called for new leadership.

How does the vote work?

It is a secret ballot of Democratic senators behind closed doors, expected in early December. A candidate needs 28 votes. That rises to 29 if Mary Peltola wins Alaska’s Senate race, where she leads Republican Dan Sullivan and counting is still going on. The secrecy matters: senators who publicly stay neutral can vote either way without anyone knowing.

What does it mean outside Washington?

The Senate leader decides which bills reach the floor. Schumer’s plan for the new Congress is to bring up bills such as restoring Obamacare subsidies and banning insider trading, and force Republicans to vote on them. Van Hollen’s plan points at the funding fight first. For America’s allies, including Australia, the difference is how hard the new Democratic Senate pushes on the Iran war, which has disrupted shipping through the Strait of Hormuz since February.

Has this happened before?

Senate Democrats last had a contested leadership race in 1994. Leaders usually step aside rather than lose a vote, which is why Schumer’s insistence that he has the numbers, and Van Hollen’s insistence on running anyway, makes this a rare fight in the open.