He is now more than halfway to the 1.237 he needs for the nomination.
The worrisome thing is that as Gerald Ford proved in 1976 and as Ike proved in 1952, contested conventions are like horseshoes. Close counts.
It's not just about denying Trump those 1,237 votes. History and the psychology of these things say that if he can get anywhere near that number- say, within 100 or 150- political opportunism will start to come into play, and people will start falling all over each other to put him over the top.
So this is worrisome. Trump is halfway there with a little more than half the delegates selected. And it can't even be close if the convention is going to turn to an electable alternative in July.