About nine hours after U.S. Rep. Seth Moulton officially announced on Wednesday that he’s pursuing a primary challenge against incumbent U.S. Senator Ed Markey, former state Rep. Jamie Belsito announced that she’s running for the 6th district seat that Moulton will be leaving behind.

The theme of her Facebook post — beyond her qualifications for the job — was the idea that Democrats have been feckless when it comes to standing up to President Donald Trump during his second term. As Belsito put it in her announcement, “It’s time for Democrats who fight and win, not apologize.”

She elaborated on that idea in an interview with GBH News.

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“Right now, Donald Trump is bragging about staying in office for a third term,” Belsito said. ”He’s got hats made saying ‘2028.’ He’s sending out the National Guard. He’s threatened Boston to pull the World Cup, which is unbelievable ... He’s kidnapping Americans. He’s in our communities. He’s destroying programs like Medicaid and the Department of Education. And we’re sitting back watching! We’re sitting back watching it.”

That idea — that Democratic resistance to Trump isn’t nearly as vigorous or effective as it should be — was advanced by Moulton himself in his campaign kickoff video as the Salem Democrat explained his decision to primary Markey next year.

“Democrats have failed to stop Donald Trump’s harmful, racist agenda,” Moulton says at one point. “Our party has clung to the status quo, insisted on using the same old playbook, and isn’t fighting hard enough.”

It was also articulated by another candidate who’s jumped in the race to replace Moulton — former Biden Administration official and Boston mayoral chief of staff Dan Koh — in his own kickoff video, which was released Thursday.

“While Donald Trump tramples our democracy, undermines our constitution, and tries to silence us, prices are skyrocketing, families are hurting, and it feels like no one’s doing anything about it,” Koh says in the video. “Democrats just aren’t getting it done in D.C. We all know it.”

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Koh previously ran for Congress in 2018 in the 3rd district, finishing second in the Democratic primary by less than 150 votes to U.S. Rep. Lori Trahan, who still holds the seat.

Bethany Andres-Beck, a political newcomer who has been running against Moulton for months, is also unimpressed with the Democratic Party, telling Boston.com in July: “It’s really frustrating watching the party fail to rise to the moment. I don’t think that there’s any substitute for authenticity and it feels like the Democratic Party desperately wants to be liked. I just don’t feel like that’s how you make good policy. That’s not how you build communities. You have to actually know people.”

Could disaffection with the Democratic establishment become the “central message in the race,” as Politico’s Kelly Garritty suggests? Perhaps — though Garrity also notes that several possible entries into the 6th district contest still haven’t made up their minds about whether to run or not.

For now, at least, it’s an indication of how many Democrats from different backgrounds feel their party still hasn’t figured out how to push back against Trump, even though they’ve been running against him in one way or another for roughly a decade now. That may be the biggest story in American politics today.