By Bobby Caina Calvan Associated Press

HELENA, Mont. (AP) – Montana Attorney General Tim Fox announced Monday that he will not run for the U.S. Senate seat now occupied by Democrat Jon Tester, a two-term incumbent who is considered among the most vulnerable Senate Democrats in 2018.

National and state party leaders had been courting Fox to run against Tester after the GOP’s first choice, former U.S. Rep. Ryan Zinke, took a cabinet position with President Donald Trump as secretary of the U.S. Department of the Interior.

Fox told The Associated Press that he still had a lot of work to do as attorney general, an office in which he was just re-elected to last November.

“I ran for attorney general because I wanted to improve the state of Montana, and I’m proud of what my team and I have accomplished since I came into office,” Fox said in his statement. “I’m going to keep my promises to the people of Montana and continue fighting for justice throughout my full second term.”

Fox’s decision means Republicans will have to scramble to find another candidate. Two lesser known candidates have already announced bids, including state Sen. Al Olszewski and businessman Troy Downing, who heads a California-based self-storage company.

Tester’s campaign said it was prepared for any Republican candidate.

“I don’t think that there’s any question that 2018 is going to be a tough race, but I also believe that whoever ends up running against Jon Tester is going to have a really tough race,” said Chris Meagher, a spokesman for the Montana Democratic Party.

The development also further muddled the field for the governor’s race in 2020. Fox immediately becomes a leading contender for that post, although other Republicans are said to be eying the seat, including the state’s newly elected congressman, Greg Gianforte.

Gianforte, a Republican who unsuccessfully sought the governor’s mansion last year, has yet to be sworn in as the state’s sole representative in the U.S. House and has yet to face a misdemeanor assault charge stemming from an election eve confrontation with a reporter.

The reporter said he was assaulted by Gianforte while trying to interview him about a GOP-authored health care bill. Following the May 24 altercation, Jacobs tweeted: “Greg Gianforte just body slammed me and broke my glasses.”

Gianforte filed papers last Friday for a 2018 re-election bid.

Republicans now hold all but two of Montana’s statewide offices—Tester’s Senate seat and the governorship—and would relish an opportunity to snatch away Tester’s post.

In 2012, Tester narrowly fended off a challenge from then-U.S. Rep. Denny Rehberg.

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