"There is so much work to be done all over the country fighting on behalf of women and standing up against a concerted effort to roll back the clock on our freedoms and opportunities," she continued in a statement. 

"I will always be committed to the people who taught me that those freedoms are something we must keep fighting to protect. Montana is my home and I will always want to be a part of its future."

The powerful Democratic strategist would have given the party a recruit who could raise serious money and force the GOP to spend in the state. But Schriock's years in D.C. — and strong support for abortion rights — may have complicated her chances at winning the seat. 

Montana state Superintendent Denise Juneau (D), Montana Lieutenant Gov. John Walsh (D), Montana Supreme Court Justice Brian Morris (D) and state Sen. Kendall Van Dyke (D) have also been mentioned as possible candidates, though none would start with the national connections that Schriock has.

Sen. Max BaucusMax Sieben BaucusBernie Sanders flexes power on single-payer ObamaCare architect supports single-payer system Trump has yet to travel west as president MORE (D-Mont.) is retiring, and Schweitzer's (D) surprise decision not to run has left Democrats scrambling for a top-tier candidate to run.

Rep. Steve Daines (Mont.) is the most likely Republican candidate, though he hasn't jumped into the race.