Donald Trump’s effort to reset his campaign following defeat in Wisconsin showed no signs of paying off this weekend, as a series of technical failures by his campaign set his hopes back even further. From Thursday to Saturday, Trump suffered setbacks in Colorado, Iowa, Michigan, South Carolina and Indiana that raise new doubts about his campaign’s preparedness for the long slog of delegate hunting as the GOP race approaches a possible contested convention. He lost the battle on two fronts. Cruz picked up 28 pledged delegates in Colorado. In the other states, rival campaigns were able to place dozens of...