The senator steals a march on potential 2016 rivals. By Robert Costa The early dynamics of the 2016 Republican presidential-primary contest were jolted on the morning of Friday, July 19, in a ballroom on the third floor of the Marriott hotel in downtown Des Moines. It was there, in front of coffee-sipping pastors, that Senator Ted Cruz of Texas wowed the kingmakers of the Iowa caucuses for the first time. Without notes and ignoring the podium, he roamed the carpeted dais for nearly an hour, quoting Scripture and musing about the Democrats and their occasional affinity for Satan. The reception...