Fong Khang hoped his legal troubles were over when the Minnesota Board of Pardons unanimously agreed on Jan. 20 to set aside eight criminal convictions that were threatening his ability to remain in the United States. His wife burst into tears at the news, and a grateful Khang thanked the board, according to a videotape of the hearing. He said he was “deeply ashamed” of a string of thefts he committed nearly 20 years ago, crimes that had him in and out of jail until 2010. Less than 24 hours later, federal agents stopped Khang on his way to work...