On Wednesday, Trump warned of “riots” at the Republican National Convention in July if he arrives with fewer than the required number of delegates to clinch the nomination, but still more than his rivals have, and doesn’t get the party’s nod.

“If you disenfranchise those people, and you say, ‘Well, I’m sorry, but you’re 100 votes short,’ even though the next one is 500 votes short, I think you would have problems like you’ve never seen before. I think bad things would happen,” Trump said. “I wouldn’t lead it, but I think bad things would happen.”

Kasich has attempted to draw a contrast between himself and his mud-slinging rivals by giving his candidacy a sunny, positive tone. While taking issue with the Trump campaign’s “toxic atmosphere,” he has largely refrained from criticizing Trump the man. Kasich has dodged questions over Trump’s fitness for the presidency in TV interviews and has stuck by his pledge to support the eventual GOP nominee even if that person is Trump.

The strategy has had some success: On Tuesday, Kasich won his home state’s GOP primary.