Haley Stevens

Officially, Senator Chuck Schumer of New York, the Democratic minority leader, has no preferred candidate in his party’s unruly primary race for Senate in Michigan.

But in conversations with major donors behind closed doors, Mr. Schumer, who for two decades has tried to elevate his favored primary candidates in battleground states, has been clear about his desire.

He is asking party donors to support Representative Haley Stevens, a moderate candidate running against two more progressive Democrats, according to four people briefed on the communications over the last few weeks, who spoke on the condition of anonymity to disclose private conversations.