Mark A. Gonzalez, a progressive district legal professional in Nueces County, Texas, took an uncommon tack when he got here underneath fireplace from conservatives who didn’t like how he was doing his job.

He resigned — to run for the United States Senate.

Mr. Gonzalez introduced Tuesday that he would be a part of a big subject of candidates within the Democratic major to problem Senator Ted Cruz subsequent 12 months, essentially the most distinguished of whom is Representative Colin Allred. In an interview, Mr. Gonzalez mentioned his choice was immediately tied to efforts to remove him from his elected office.

“Prior to that, I hadn’t really had any more taste or want for politics,” he mentioned. But “with the petition and some of the stuff that’s been going on at least statewide, it just kind of — I don’t know if the word is just angered me or incited me or something — and so I just decided that I don’t want to represent or try to represent just Nueces County. I want to represent Texans that want change.”

He mentioned the opposite points that animated him included preserving abortion rights and voting rights, and combating conservative efforts to restrict the educating of topics just like the United States’ racial historical past.

His campaign announcement video highlights Mr. Cruz’s choice to go away Texas for a vacation in Cancún in 2021 whereas the state was coping with a disastrous winter storm, and contrasts that call with a clip of Mr. Gonzalez throughout the identical storm, asking Nueces County residents to inform his workplace of any incidents of worth gouging. Mr. Cruz, a Republican searching for a 3rd time period within the Senate, fended off an unexpectedly fierce problem from Beto O’Rourke, a Democrat, in 2018. He received that race by about 2.5 percentage points, two years after Donald J. Trump had received the state by nine points.

It might be an uphill battle for any Democrat to unseat Mr. Cruz given Texas’ partisan leanings, however his is without doubt one of the few Republican-held Senate seats — together with one in Florida — that Democrats might goal amid a troublesome 2024 map. By distinction, Republicans see pickup alternatives in eight pink or swing states. Democrats at present management the Senate by a slender margin.

Mr. Gonzalez does, nevertheless, have a report of successful tough races. He was elected in Nueces County, dwelling to the town of Corpus Christi, in 2016 and 2020, at the same time as Mr. Trump narrowly received the county. He beforehand mentioned he wouldn’t run for re-election as district legal professional.

“I think that more Texans probably can identify with a guy like me,” he mentioned when requested what set him aside from the opposite Democratic candidates — a man like him that means, amongst different issues, somebody from a low-income household who has a prison report.

He added: “We have strong family values, we believe in small government, but I also believe in opportunity and giving people chances, and I think most Texans feel that way.”

In his announcement video and his resignation letter to Gov. Greg Abbott, Mr. Gonzalez took the weird step of emphasizing a component of his background that many candidates may need sidestepped: a drunk-driving arrest when he was 19. In the resignation letter, he mentioned he had taken duty and pleaded responsible, then been dismayed to see the same charges dismissed for a defendant who, not like Mr. Gonzalez, might afford a lawyer.

“It dawned on me that the wealthy and well-connected have a different criminal legal system applied to them and accusations against them than everyone else does,” he wrote. “My ignorance of the system was detrimental to my life and has been to so many others just like me.”

Mr. Gonzalez additionally drew consideration to an effort by conservative activists to take away him from workplace, which his resignation has made moot. The conservative petition accused him of incompetence and official misconduct.

The petition was each particular and broad. Specifically, it accused him of mishandling two capital homicide circumstances. But it additionally accused him of getting “intentionally nullified duly enacted laws of his oath of office,” reflecting a rising sample of right-wing makes an attempt to take away progressive prosecutors who’ve used their discretion to hunt decrease sentences or to say no to cost sure crimes.

“They want to use me as a sacrificial lamb to send a foreboding message to other duly elected D.A.s in Texas who exercise their discretion,” Mr. Gonzalez wrote of state Republicans in his resignation letter.

“I will not be used that way, nor will I run from a fight,” he added. “Quite the opposite, in fact.”