Colorado Attorney General Phil Weiser has won the state’s Democratic primary for governor, NBC News projects, upsetting Sen. Michael Bennet after a campaign that centered on who would be more effective in standing up to President Donald Trump. While both candidates have long been mainstays in Colorado Democratic politics, Weiser entered the race as the underdog. His victory signals that his antiestablishment message broke through in an environment where Democrats across the country have expressed frustration with the status quo, including in their own party.Weiser will now head into the general election to succeed term-limited Democratic Gov. Jared Polis as the front-runner in a state where voters have not elected a Republican governor in more than two decades. Colorado’s GOP primary for governor features Victor Marx, a Marine veteran and ministry leader; state Sen. Barb Kirkmeyer; and state Rep. Scott Bottoms. Bennet, who has served in the U.S. Senate for 17 years and ran unsuccessfully for the Democratic presidential nomination in 2020, was seen as a clear favorite when he launched his gubernatorial primary bid last year. But Weiser, who is serving his second term as attorney general, gained traction as the two candidates traded attacks over their anti-Trump credentials in a race where there was little daylight between them on policy. Both have pushed affordability, housing and environmental issues, as well as fighting Trump’s immigration agenda, as top priorities.Weiser has attacked Bennet for confirming several of Trump’s Cabinet nominees as a member of the Senate, while casting him as a Washington insider. “The Democratic Party doesn’t show up, listen and fight,” Weiser said at one debate this month. During another recent debate, Weiser said that “Congress is not doing its job” and that “Congress should be a check on a lawless, bullying administration. It hasn’t been.” Weiser has also attacked Bennet for missing votes as a senator — though one of his lines on the stump has been “Michael Bennet for Senate, Phil Weiser for governor.”Meanwhile, Bennet has criticized Weiser for not being more aggressive as the state’s top lawyer in suing the Trump administration. “The attorney general says he’s really tough, but was completely missing in action in Donald Trump’s first term when more than 20 Democratic attorneys general across this country filed a lawsuit against the administration because they were separating kids from their parents at the border,” Bennet said at one debate. “It’s not about the lawsuits he brought. It’s the lawsuits he didn’t bring.”Bennet has voted in favor of eight of Trump’s Cabinet nominees and against 15 of them during the president’s second term. For his part, Weiser has filed or joined at least 50 lawsuits against the administration.Since Jan. 1, 2025, Bennet’s campaign and allied outside groups have outspent the pro-Weiser camp on ads by almost 2-to-1, according to the ad-tracking firm AdImpact. Ads on both sides focus heavily on an anti-Trump message. “People ask me why I’m running for governor. My answer? Because I’m not willing to allow Donald Trump to define Colorado’s future,” Bennet said in one of his ads.Weiser said in one ad: “I’ll always stand up to bullies. Especially Donald Trump. Congress isn’t doing it — but I am.”Before he was elected attorney general in 2018, Weiser was the dean of the University of Colorado Law School.Bennet was first appointed to the Senate in 2009 to serve out the remainder of Sen. Ken Salazar’s term after he was appointed to a position in President Barack Obama’s Cabinet. He was last re-elected in 2022, so Bennet will remain in the Senate until 2029.