Rep. Steve DainesSteven (Steve) David DainesTax bill raises red flags for Senate GOP Overnight Energy: EPA kicking scientists who get grants off advisory boards High stakes as Trump heads to Hill MORE (R-Mont.) officially announced his Senate bid on Wednesday, giving Republicans a top-tier recruit for retiring Sen. Max Baucus's (D-Mont.) seat.

"I humbly ask for your support to be Montana's senator, " Daines said at an event in his hometown of Bozeman.

The freshman senator has long been expected to run, and sources told The Hill last week that he would announce Wednesday.

Daines begins the race as a slight favorite to succeed Baucus in the GOP-leaning state. National Democrats are hopeful Montana Lt. Gov. John Walsh (D) will run a strong race, though he got a primary challenger in former Montana Lt. Gov. John Bohlinger (D) on Wednesday.