Kasich, who has no chance to win, remains in the race to prevent Trump from getting enough delegates.
Rubio, who "suspended" his campaign after losing to Trump in Florida, might as well be doing the same thing because, contrary to standard practice, he's trying to bind his delegates to himself instead of releasing them.
From the story here:
"No one has ever really tested this, the idea has always been that when you suspend, you're out," said a senior Republican in Washington, D.C., who did not want to publicly discuss a contested convention.
"No candidate has ever said, 'I want to suspend — but I also want the delegates,'" according to the source. ...
While Rubio is going to great lengths to hold onto his delegates, there is no doubt he has stopped competing in future primaries. This week he sent a signed affidavit to have his name removed from the ballot in California, which awards 172 delegates on the last voting day in June.