Van Hollen challenge report lifts his bets, but Schumer is still likely Senate leader

Traders still expect Chuck Schumer to be the next Senate majority leader, but they gave Chris Van Hollen a sharply better chance on Monday after a report that he is open to challenging him. Van Hollen, the runner-up in the betting, moved from a long shot to unlikely to win the post.

Politico reported on Monday, citing a person familiar with his thinking, that Van Hollen is open to running against Schumer for Senate Democratic leader. Van Hollen has not announced a candidacy. An aide had said earlier that he would not pursue the job. Expectations for Schumer slipped at the same time, from all but certain to likely, so the report has dented his standing without displacing him as the favorite.

The move came late in the day. Through the weekend, bets on Van Hollen had faded. They rose on Friday, fell back on Saturday and sank further on Sunday to their lowest point since tracking began. They held near that low through Monday morning, then jumped in the afternoon as the Politico report spread.

Democrats won control of the Senate in the Nov. 3 election, which leaves their caucus to pick the next majority leader. CBS projected that Democrats would hold at least 54 seats. Schumer, the current Democratic leader, said on Nov. 4 that he expected to be reelected to lead the caucus.

Van Hollen's position has shifted several times. He has called for a discussion before senators commit to a leader, and Senator-elect Abdul El-Sayed has said he would support Van Hollen if he ran. On Friday, a Van Hollen aide told CBS that he would not pursue the post. On Saturday, Van Hollen said Schumer should not receive a "blank check" to be majority leader. The new reporting is a change from the aide's earlier account. The Associated Press reports that Schumer is still expected to have enough votes.

Senate Democrats will choose their leader by closed ballot, which makes support hard to measure in advance. The outcome is decided by the first announcement of the next majority leader from the party holding the majority.

Several things to watch: whether Van Hollen formally enters the race, whether other senators endorse a challenger or Schumer, and when the caucus sets its vote. Until one of those happens, the reason for the sudden shift in bets rests on a single report of Van Hollen's thinking, not a declared challenge.