Memo to Republican leaders: Be careful what you wish for. Hoping to avoid a repeat of the messy fight for the Republican nomination in 2012, the party drew up a calendar and delegate-selection rules intended to allow a front-runner to wrap things up quickly. Now, with Republicans voting in 11 states on Tuesday, the worst fears of the party’s establishment are coming true: Donald J. Trump could all but seal his path to the nomination in a case of unintended consequences for the party leadership, which vehemently opposes him. --snip-- A majority of the 595 delegates at stake that day...