That wasn’t Baker’s first tangle with a prosecutor. In 1989, then-St. Louis Circuit Attorney George Peach vowed to disqualify Baker for the remaining three years of his term. Baker had tossed nine felony convictions returned by a jury, concluding there was insufficient evidence.

“It’s always a surprise when a prosecutor does it,” said defense lawyer Eric Selig, because it could suggest other political motivations at play.

Though requesting a new judge may be more common among the defense bar, lawyers on either side of criminal cases typically do it only after thoughtful consideration, legal observers say. Defense lawyers sometimes request a transfer when they know their assigned judge has a reputation for giving stiffer sentences for certain crimes.

“You have to think about the consequences for other cases,” said John Ammann, a law professor at St. Louis University. “Lawyers do it very cautiously just because of the ramifications it might have down the road and your reputation with the judges.”

Because McCulloch is stepping down at the end of the month, it’s probable he’s “not too worried about repercussions, so he probably feels more free to do it now,” Ammann said.