FARGO, N.D. — Ted Cruz’s preferred candidates won the vast majority of convention delegates available in North Dakota over the weekend, taking 18 of 25 slots in the state in another show of organizational strength over Donald Trump. It’s still not clear how loyal all of Cruz’s slate will be if the Republican nomination heads to a contested convention in Cleveland, as several included on it told POLITICO they were only leaning toward Cruz, or simply opposed to Trump. But the result was bad news for Trump, who may need unbound delegates like those in North Dakota to lift him...