It has certainly been a meaningful eight days in the Republican primary. Ted Cruz smashed Donald Trump in Wisconsin’s April 5 primary, and his probability of victory certainly jumped up and Trump’s went down. Seven days later Trump is right back where he started, as Cruz continues to rise. Trump is holding his own, because the biggest story of April 5 turned out to be John Kasich’s underwhelming performance. He was instantly no longer as legitimate of strategic vote and/or Cruz looks too legitimate for the Party pass over both Trump and Cruz. That is probably why Paul Ryan, the presumptive front-runner for “white-knight” candidate (i.e., the likely person to win the nomination if it went to someone who never ran for president) dropped out of contention today.
Majority Delegates 25%: There is 25% likelihood that Trump gets 1,237 pledged delegates.
First Ballot 40%: There is an additional 21% that Trump has between 1,200 and 1,236 delegates. With a 40% likelihood of winning on the first ballot, there is a high probability that if Trump falls less than 36 delegates short of 1,237, he will pick up the nomination on the first ballot with unbound delegates.
Second+ Ballot 60%: If there is a second ballot, Trump is 16% to win the nomination, Cruz is 36%, and Kasich 7%. Most likely this is a two person race, because Rule 40 will be retained; no one would be able to get votes at the Convention unless they won the majority of delegates in eight states. Conditional on there being a second ballot, Cruz is 60% to win, Trump 41% to win, and Kasich 19%.