Wisconsin looms as tipping point for Trump

Several weeks ago, after winning a handful of Super Tuesday contests, Trump called on party members to coalesce around him. While there were still mixed feelings, some Republicans started to see the benefit of doing so in order to avoid a protracted battle. Some even thought he would be coachable and able to change his tune to defeat the likely Democratic nominee, Hillary Clinton, in November.

But those days seem to be in the rear-view mirror. Both Cruz and Kasich have questioned whether they could support the eventual nominee if it is Trump, a backing away from their so-called loyalty pledge. For his part, Trump abandoned the pledge altogether last week, which jeopardizes his hold on the 50 delegates he earned in South Carolina.

At this stage, the race is less about narrative shaping and more about the nitty-gritty of delegate counting, as candidates and Republican leaders are preparing for the prospect of an open convention. Those hoping to stop Trump believe their chances improve greatly on a second ballot at the convention, as long as they can prevent him from winning the magic number before then.