With Democrats losing control of the Senate this election cycle, Senator Claire McCaskill (D., Mo.) appears to have soured on Harry Reid and told reporters on Thursday she would not back him as the caucus’s leader next year.

“I will not,” she said when asked if she would back Reid, according to Roll Call.

McCaskill is the first member to publicly oppose Reid’s return as the Democratic leader, although no Democrat has stepped forward to challenge him.

Meanwhile, Republicans officially and unanimously selected Mitch McConnell (R., Ky.) as the Senate’s new majority leader on Thursday.