The Wall Street Journal chides Trump and Cruz for wanting Kasich to drop out:

Mr. Cruz wants Mr. Kasich out now because he figures the delegates in Cleveland will choose Mr. Cruz if the choice is down to him and Mr. Trump. But if Mr. Kasich is still an option, the delegates might favor him as a better November candidate.

Kasich is arguably the most competitive general election candidate of the three Republicans, but in practice a contested convention that gave the nomination to Kasich would lead to general election disaster. Nominating Kasich would mean overruling the preferences of 70-80% of the party’s voters. That would all but guarantee that large numbers of both Trump and Cruz supporters would refuse to back the nominee in the fall, and some of them might write off the party all together in the future. In other words, Kasich can’t be a “better November candidate” because a significant bloc of Republican voters would not rally behind a nominee most primary voters didn’t want. That’s also why the Paul Ryan scenario that some Republicans are trying to float makes so little sense. Kasich has at least been a candidate and won some votes in primaries and caucuses, but nominating Ryan and completely dismissing the preferences of the voters would be an act of self-immolation so extraordinary that only Republican strategists would think it was smart. Neither Kasich nor Ryan would recover from obtaining the nomination this way. Such a nominee would be hamstrung by the fact that he was foisted on the party against the wishes of the vast majority of Republicans across the country. That realistically leaves the GOP with Trump or Cruz, which has been the only plausible choice facing Republicans for months.

Kasich’s continued presence in the race makes it more difficult for Trump in blue-state primaries than it would otherwise be, since he is taking some moderate and “somewhat” conservative voters that might back Trump if he weren’t in the race. He probably won’t win another race in the next two months, but he can keep Trump from running away with it in the meantime. Kasich has been repeatedly attacked for enabling Trump, but the reality is that he will be the one doing the most to get in Trump’s way over the next eight weeks.