Chicago’s top federal prosecutor stepped carefully through a potential political minefield on Wednesday.In a news conference, U.S. Attorney John R. Lausch Jr. politely but firmly declined to answer most of the questions posed to him about President Donald Trump and members of his administration.The conference was held about a year after Lausch, a Trump appointee, took his position as head of the U.S. Attorney’s Office for the Northern District of Illinois.“I don’t have any opinion on that,&rdquo …