In the past few years, Keith Ellison has become a national figure. The Minnesota congressman and deputy chair of the Democratic National Committee has become an icon to progressives and a hate figure to conservatives.

The first Muslim ever elected to Congress in 2006, Ellison leveraged his role as an active surrogate for Bernie Sanders’s 2016 presidential campaign to become an important voice on the left of the Democratic party.

However, on the eve of a midterm election where his party seems poised to retake control of the House of Representatives for the first time in nearly a decade, the 54-year-old announced that he was leaving Congress in order to run in a competitive Democratic primary for Minnesota attorney general.

Ellison explained his reasoning in a June interview with the Guardian in a Duluth coffee shop as the six-term Democrat prepared to take part in protests and marches against Donald Trump’s visit to the city.

He described state attorney general as “the one job in politics where you can do the most good as quickly as possible”.

Ellison used “the horror at the border” with Trump’s family separation policy as one example where “in order for me to do anything about it as member of Congress, anything real, I gotta have enough people in Congress to vote for it”. In contrast, he noted state attorneys general were looking at litigation on the issue.

I basically made a choice about what end of the fight I want to be in. Keith Ellison

Ellison said: “I basically made a choice about what end of the fight I want to be in. Writing the law is super important, writing federal law is super important, but also enforcing the law is equally important and that’s just the end of it that I’d rather be focused on at this point.”

He added that what he saw as some of the biggest civil rights issues facing Americans were in areas where a state attorney general could intervene.

“Whether it’s telling people they can’t come here because of their religion, companies charging women more because they are women, kicking out 800,000 people who only know America as their home … I can speak out as a member of Congress. I can write a bill, but I can’t do anything right away about it,” he said.

The Minnesota Democrat told the Guardian that he had been thinking about leaving Congress and running for state attorney general “for years”. However, he was spurred to run when current incumbent Lori Swanson decided to mount a gubernatorial bid. “I didn’t think I needed to leave Congress to run against a Democratic incumbent,” said Ellison “but when the seat became open, I said, ‘This is what we gotta do.’”

Democratic voters go to polls on 14 August to select a nominee for Minnesota attorney general.

Ellison is the second congressional Democrat to leave Capitol Hill to seek a state attorney general position since Trump’s election. In 2016, Xavier Becerra left a position in the House Democratic leadership to replace Kamala Harris as California attorney general upon her election to the Senate.

He talked of potential attorney general peers like a schoolboy talking about star athletes. Maura Healey of Massachusetts was “killing it” while Becerra, as well as Mark Herring of Virginia, were “awesome”. Ellison enthused about Herring: “He’s fighting the battle. He was one of the first people out on the whole travel ban, travel slash Muslim ban.”

Ellison saw other opportunities to be what he called a “let’s go AG” and not a “me too AG”. He touted the opportunities to “strengthen the economic prospects of working- and middle-class Americans”. Ellison noted that “having antitrust authority, [the Minnesota attorney general] can band with other attorneys general and say maybe there should not be one company that dominates 75% of the market as Amazon is approaching or Google is approaching, maybe there should be three companies that do chicken in the United States”.

In his opinion, “We need to deconcentrate markets so that small companies can emerge [and] so startups can grow.”

Ellison did not demonstrate any frustration with Congress nor did he seem to express much regret about giving up the seniority that he had accumulated in over a decade of service in Washington.

“I am not looking to climb some career ladder,” said Ellison. “I don’t give a damn about that. What I care about is how can I help the most people. How can I be maximally effective in defense of people’s economic and social rights, that’s what I care about.”