Donald Trump had a big night last night; as expected he swept the five states in the so-called "Acela Primary". What made the night special for Trump was two things: First, market-based forecasts had him at 40 percent to win all five state with 50 percent or more of the vote. So, Trump's 58 percent in CT, 61 percent DE, 54 percent in MD, 57 percent in PA, and 64 percent in RI was bigger than expected. Second, Trump did well in securing the "pledges" of unbound delegates in Pennsylvania. While the final number is not yet clear, between delegates saying they will vote for him or vote for winner of Congressional District, he should get well more than half of the 54 unbound delegates on the first ballot at the convention.
So, it is not surprising that Trump surged last night from 75 percent likelihood to win the nomination to 83 percent this morning. Most of this increase came at the expensive of Ted Cruz, because he is the only one left to give!
More technically, Trump is now at 66 percent likely to reach the magic number of 1,237 pledged delegates. But, he is 79 percent likely to win the on the first ballot. The markets have been clear about this for months now; Trump does not need 1,237 pledged delegates to win. He needs closer to 1,200 pledged delegates, depending on how the unbound delegates are counted (here we are using the AP totals). Beyond Pennsylvania there are going to be over 100 completely unbound delegates, some of whom will vote for Trump in the first ballot. At this point, should he somehow lose the first ballot, he will be highly unlikely to win the nomination on a subsequent ballot.
The Cruz and John Kasich pact has so far failed to stop Trump in Indiana. He is 70 percent likely to win as of this morning, up from about 67 percent when the non-aggression pact was announced. It is hard for alliances to hold -- if voters heed the call many Kasich voters would jump to Cruz or Trump, and it is hard to get voters to vote strategically. A win in Indiana would be huge for Trump, but not necessary to get the nomination.
On the Democratic side, Hillary Clinton is now 98 percent to win the Democratic nomination. This is little changed over the last week.