Obviously the Republican presidential contest is a real mess. The biggest question is whether anyone can attract enough delegates to get a majority. If not, we will have an open convention and anything could happen. Certainly Trump has the best chance so I did a little analysis. If you want to skip all the gory details, go to the last paragraph.
Generally states award delegates in one of three ways: proportional, winner take all or conditional winner take all. In the latter category, the allocation is proportional unless the winner gets a majority of the votes. There are a bunch of other mind-numbing rules but I won’t get into that.
It takes 1,237 delegates to get a majority. So far Trump has 458. That means he still needs to get 779 more delegates. So far he has never received a majority of the vote in a single state. If that continues, then all of the conditional winner take all states would be awarded on proportional basis. So far he has been getting 40% of the delegates that are awarded proportionally. If that trend continues, he would pick up 413 more delegates, giving him 871. He would still need 366.
There are twelve states or territories left that are winner take all. They have 409 delegates. I think it is extremely difficult for him to pull it off. He does best when states let Democrats and Independents vote. Most of these states have a closed primary.
In conclusion, if Trump keeps going like he has been, he has virtually no shot at getting enough delegates. He has to start winning the majority of votes in states, something he has not done so far.