Montana, which will host one of the nation’s hottest Senate contests this fall, moved into general election mode after its Tuesday primaries officially set out the congressional contenders.

First-term Republican Sen. Steve Daines, whom CQ Roll Call ranks as among the most vulnerable in the chamber, will face the state’s Democratic governor, Steve Bullock, in a race that has already drawn big political money from outside groups. Neither had a serious primary threat Tuesday.

Meanwhile, former state Rep. Kathleen Williams easily won the Democratic nomination for the state’s at-large House seat, defeating state Rep. Tom Winter. With 27 percent of precincts reporting, she was ahead with 90 percent of the vote when The Associated Press called the race.

Williams will face state Auditor Matt Rosendale, who bested a six-candidate Republican field that included Montana Secretary of State Corey Stapleton. With 61 percent of precincts reporting, Rosendale led Stapleton, 48 percent to 34 percent, when the AP called the race.

Williams’ relatively smooth primary this cycle is a contrast to her intraparty win in 2018 when it took more of an investment for her to pull out a victory. She also entered the race months earlier this time and had already banked $1.2 million by May 13.

Two years ago, she lost by 5 points to GOP Rep. Greg Gianforte, who won the GOP primary for governor Tuesday.

Rosendale is similarly looking at a do-over this fall after losing a bid for Senate in 2018 to Democrat Jon Tester. He also ran for the House seat in 2014, losing a GOP primary to Ryan Zinke.

A favorite of GOP outside groups, Rosendale benefited from the support of the anti-tax Club for Growth, which spent money to boost his candidacy in the primary.

Rosendale also had $900,000 in the bank as of May 13.

Montana voted for President Donald Trump by more than 20 points in 2016, the same year it also reelected Bullock as governor by 4 points.

“We are one of the big split-ticket voter states,” said David Parker, who chairs the political science department at Montana State University and conducts political polling. “Money tends to come here because we’re really cheap in terms of TV ad rates.  In an environment where the Senate is much more in play, this is a state that gives you a path.”

Because of the coronavirus pandemic, Bullock signed an executive order allowing counties to conduct Tuesday’s election entirely by mail, and all 56 counties decided to do so, according to Montana Public Radio. In-person voting was also an option.

Though the Senate race, which will play a pivotal role in determining which party controls the chamber in 2021, is at the forefront, the House contest, too, may be competitive — at the very least, it will be costly. The Democratic Congressional Campaign Committee added Williams last month to its Red to Blue program for strong recruits, which provides organizational and fundraising resources for campaigns.

“Women candidates won the majority in 2018 — and they’re going to expand it in 2020,” DCCC Chairwoman Cheri Bustos said in a statement announcing the addition of Williams and other candidates to the program. “These candidates are the reason Democrats are poised to expand the firewall against Republican attempts to take away Americans’ health coverage during a deadly pandemic.”

Parker said Bullock’s high-profile Senate challenge could have a down-ballot effect in Williams’ favor, noting that she came relatively close in 2018 when she lost to Gianforte by about 25,000 votes.

Inside Elections with Nathan L. Gonzales rates the Montana Senate race Lean Republican and the contest for the at-large House seat Likely Republican.