The man whose court challenges have stalled financing for the new Minnesota Vikings stadium is a longtime activist, perennial candidate and licensed nurse who has picked up some basic legal skills from a paralegal course.

If Doug Mann’s name is familiar, it’s likely because he was one of 35 candidates in Minneapolis’ mayoral race last year. He ran for City Council in 2005 and this year’s attempt to be on the school board will be his ninth try. He has never won.

“One thing about him, he’s tenacious,” said fellow activist Ron Edwards, who has known Mann for years.

Tenacious enough that when his first lawsuit against Vikings stadium financing didn’t prevail on the merits, he appealed earlier this month. And then filed a second lawsuit Friday on the eve of a planned stadium bonds, with his wife, Linda, a nonpracticing attorney, and activist David Tilsen joining. That’s thrown at least a temporary monkey wrench into stadium financing.

Mann, 57, said he didn’t file his stadium lawsuits earlier because he was working long hours as a licensed professional nurse while remodeling the Folwell neighborhood home the couple bought in 2012. But he had more free time when he was laid off from his job at a group home, tending to adults who are in life support.

He’d gained some legal basics from a paralegal course for nurses, which helped his research, but often seems fumbling in court hearings.

“It’s a pretty uneven match,” he conceded Monday. “I’m up against pretty experienced attorneys, who are very smooth.” But he embarrassed city attorneys when a judge agreed with him that the city’s sales tax financing of the stadium would trigger a voter referendum, absent a legislative override.

Growing up in St. Paul Park, Mann said he gained something of a reputation as a troublemaker by junior high. There was the time he boycotted a key wrestling competition to protest the exclusion of non A-team wrestlers from practices. Or the time he led a student walkout to support teachers who were doing informational picketing on their contract issues.

By the late 1990s, he’d joined the Minneapolis branch of the NAACP, and put his name down as one of the plaintiffs in its educational adequacy lawsuit arguing that the state had failed to provide an adequate education to minority students concentrated in poor, inner-city neighborhoods. But he withdrew when he disagreed with the proposed settlement, meaning he has standing to sue in the future.

How does he expect his stadium financing challenge to turn out? “I have no clue, to tell you the truth,” he confessed.

“I was actually taken by a little by surprise at the turn of events over the weekend,” he said of the bond sale postponement by state officials after his latest lawsuit. “They’re either taking it seriously or they’re being awfully theatrical.”