When Judge Gregg Costa announced his resignation from the U.S. Court of Appeals for the Fifth Circuit last month, there was surprise from the legal community. Federal judgeships are typically seen as lifetime jobs—and Costa is about 15 years from the age one is eligible to retire or take senior status.

But Costa’s phone buzzed with texts that day from FBI agents he worked with when a federal prosecutor in the Southern District of Texas. To them, Costa said, the career move wasn’t as unexpected.