Former Maryland state delegate Heather Mizeur (D) announced Thursday that she would seek her party’s nomination to challenge Rep. Andy Harris in Maryland’s 1st Congressional District, citing the Republican congressman’s behavior in the aftermath of the assault on the Capitol.

Mizeur, who unsuccessfully ran for governor in 2014, said she had not been planning on seeking a seat in Congress before the Jan. 6 siege. But as a resident of the Eastern Shore, which makes up a wide swath of the state’s deep-red 1st District, she said she felt compelled to offer voters “an alternative.”

Harris, who was just reelected to a sixth term as Maryland’s only Republican member of Congress, voted hours after the siege to object to electoral college votes for Joe Biden in Arizona and Pennsylvania. During the floor debate, he nearly got into a physical confrontation with another lawmaker. Last week, he set off a newly installed metal detector near the House chamber and was found to be carrying a gun, according to a Hill staffer who spoke on the condition of anonymity because he was not authorized to discuss the incident.

“Andy Harris’s actions on [Jan. 6] alone disqualify him from representing Maryland’s First District, but since that act of domestic terrorism, unbecoming conduct has continued to be his calling card,” Mizeur said in a video announcement Thursday. “These behaviors have stirred within me a conviction that we must present an alternative choice.”

Mizeur spent a decade working on Capitol Hill, including four years as then-Sen. John F. Kerry’s domestic policy director, and served eight years in the Maryland General Assembly. Anthony G. Brown, now a member of Congress, defeated Mizeur and Attorney General Doug Gansler in the 2014 Democratic gubernatorial primary, before he lost the general election to Larry Hogan (R), now in his second term as governor.

Mizeur then moved from Takoma Park, a liberal D.C. suburb, to the 34-acre organic farm she runs with her wife in Chestertown, Md. She returned to politics in 2017 with the launch of a nonprofit organization, Soul Force Politics, aimed at bridging divides — an ethos she said she would bring to the campaign. She interviewed Harris on Soul Force’s podcast in 2017, seeking to find common ground with him on gun-control measures despite their disagreements on the issue.

“I don’t engage in politics and look at Republican-Democrat, red-blue. I just look at all of us as people, who are in varying ways looking for belonging and connection, and it’s really been the lack of that that has created a lot of the problems we have,” Mizeur said in an interview Thursday, adding that her platform will focus on health-care reform, particularly affecting rural areas, environmental protections and civil rights, among other things.

As a Democrat, Mizeur will face steep challenges in her bid to unseat Harris, who defeated challenger Mia Mason, a transgender veteran with no background in public office, by 33 points in November.

Harris, an anesthesiologist, is a member of the conservative Freedom Caucus and has been an ardent supporter of former president Donald Trump, telling Newsmax in a recent interview that Trump’s brand of populism was the future of the Republican Party.

At least one Republican, Harford County Executive Barry Glassman, has signaled he is considering running against Harris in the 2022 primary.

A spokesman for Harris did not immediately respond to a request for comment.