Donald Trump - fresh from winning four states on Tuesday - raised the prospect of violence from his supporters if he were denied the nomination by a contested convention.
The billionaire Republican frontrunner said that if he was leading the race by hundreds of delegates - but 100 short of a clear majority - and was denied the nomination, “you’d have riots”.
“I wouldn’t lead it, but I think bad things would happen,” Mr Trump told CNN, after a night which saw him take Florida, Missouri, North Carolina and Illinois, but lose Ohio.
“I don't think you can say that we don’t get it automatically. I think you’d have riots. I think you’d have riots. I'm representing many, many millions of people”
Altough Mr Trump had a hugely successful night, and forced fellow Republican Marco Rubio to drop out of the race, his defeat in Ohio to Governor John Kasich cost him the state’s haul of 66 delegates.
This means he will have to win 60 per of the remaining delegates if he is to secure the 1,237 needed to win the party's nomination ahead of the Republican National Convention in July. He said he believed he would do, adding “I’m a closer,” he said. “I get things closed.”
But the party establishment loathes the often abrasive tycoon and is determined to stop him coming the nominee. It is possible, though unlikely, that Texas senator Ted Crus could overtake Mr Trump, but he is disliked by the party too.
Its last favored candidate, Mr Kasich, appears to believe that by depriving Mr Trump of a clean sweep on Tuesday, he could emerge as a consensus candidate.
“We are going go all the way to Cleveland and secure the Republican nomination,” he said on Tuesday night.
Mr Cruz is among those who have dismissed the idea. “There has been talk of an establishment candidate being parachuted in. I think that would be a disaster,” he said.