For the first time in months, Gov. Ron DeSantis on Saturday showed the aggressive political instincts that his allies have long insisted he would demonstrate in a contest against former President Donald J. Trump.
After headlining two successful political events in Iowa, Mr. DeSantis made an unscheduled stop in Des Moines — a move aimed at highlighting the fact that Mr. Trump had abruptly postponed a planned Saturday evening rally in the…