Senator Ted Cruz soundly defeated Donald J. Trump in the Wisconsin primary on Tuesday, breathing new life into efforts to halt Mr. Trump’s divisive presidential candidacy and dealing a blow to his chances of clinching the Republican nomination before the party’s summer convention. With more than 80 percent of precincts reporting, Mr. Cruz had received 48 percent of the vote to 34 percent for Mr. Trump. Gov. John Kasich of Ohio was a distant third with 14 percent. Mr. Trump’s loss was his most significant setback since Mr. Cruz narrowly defeated him in Iowa, the campaign’s first nominating contest. And...