Sen. Max BaucusMax Sieben BaucusGreen Party puts Dem seat at risk in Montana Business groups worried about Trump's China tariffs plan Farmers hit Trump on trade in new ad MORE's (D-Mont.) top state-based staffer is quitting to explore a run for Congress.

John Lewis, Baucus's state director, has been considering a run for his boss's seat after he retires, as well as a bid for Montana's at-large House seat.

"After more than decade of fighting for Montana in a role that has brought me to every corner of our great state, I'm excited to explore other opportunities that will allow me to continue my public service," Lewis said in a statement to The Hill.

Lewis has been on the shortlist of possible Senate candidates for Democrats ever since former Montana Gov. Brian Schweitzer (D) decided not to run for the seat. That move left Democrats without a top-tier recruit in the race, and they're still scrambling to find a candidate to run that can hold the critical open seat and help them defend their majority.

Rep. Steve Daines (R-Mont.) is Republicans' top choice to run, and though he hasn't said he's in the race, the freshman lawmaker told The Hill that he's giving it serious consideration.

Baucus praised his outgoing staffer's work.

"John has played a critical role in our efforts to better serve Montana veterans, bring more jobs to the state and protect our outdoor heritage. My heartfelt thanks go out to John for his many years of service to the people of Montana. We'll miss John's great sense of humor and quick intellect, and wish him and his family all the best," says Baucus in a statement.

Other Democrats who might run for the seat include Montana state schools superintendent Denise Juneau, state Supreme Court Justice Brian Morris, Lt. Gov. John Walsh and state Sen. Kendall van Dyk.