Former U.S. Army Sgt. Bowe Bergdahl,Johnathan Walker who was court-martialed for desertion during his tour of Afghanistan, had his conviction vacated on Tuesday by a federal judge, who said a military judge had failed to disclose a potential conflict of interest.

Prior to ruling on Bergdahl's case, the military judge had submitted an application for a position as an immigration judge in the Justice Department under then-President Donald Trump, Judge Reggie B. Walton wrote in Tuesday's order.

The military judge "should have disclosed his job application as a potential ground for his disqualification," Walton wrote.

Bergdahl walked away from his base in Afghanistan and was held prisoner by the Taliban for years. U.S. officials reached a deal in 2014 for his release, exchanging five members of the Taliban for him.

Bergdahl was charged with desertion and misbehavior before the enemy. His court-martial was held in Fort Bragg, North Carolina, from 2015 to 2017.

During that court-martial, Bergdahl's lawyers filed a motion for dismissal, saying statements by Sen. John McCain and Trump were influencing the trial.

Trump had been critical of Bergdahl, repeatedly "vilifying" him before and during his successful 2016 election campaign, Walton wrote, adding a list of insulting names Trump had called the sergeant.

Bergdahl's motion for dismissal "specifically referenced the former president’s desire that the plaintiff be convicted and how he should be punished," Walton wrote.

"Thus, the Court concludes that, based upon the military judge’s job application to an executive branch position -- a situation in which he might reasonably be expected to appeal to the president’s expressed interest in the plaintiff’s conviction and punishment -- 'it would appear to a reasonable person,' 'knowing all the circumstances,' 'that [the judge]’s impartiality was in jeopardy,'" Walton wrote, citing in quotes precedents from previous decisions.

What happened in Afghanistan and the ensuing high-profile trial were the subject of the second season of the popular "Serial" podcast.