CLEVELAND // Hillary Clinton took a monumental step toward clinching the Democratic party’s White House nomination Tuesday, while Donald Trump’s seemingly unstoppable rush to victory hit a bump in Ohio.
Mr Trump won key Republican primaries in Illinois, North Carolina and Florida - where he thumped home state Senator Marco Rubio, who immediately announced he was suspending his presidential campaign.
“This was an amazing evening,” a buoyant Mr Trump told supporters. “We’re going to win, win, win and we’re not stopping.”
Senator Rubio’s loss was a major setback for Republicans trying to stop the bellicose businessman, whose populist anti-immigrant, anti-Muslim stance they say will split the party.
But the 69-year-old Mr Trump was denied a clean sweep by Ohio Governor John Kasich, who carried his home state, a key general election battleground.
Mr Trump may now struggle to reach the 1,237 delegates necessary to avoid a challenge at the party’s nominating convention in July in Cleveland.
“The bottom line after tonight: it looks like Trump will not have a majority of delegates in July,” said Paul Beck, a professor of political science at Ohio State University.
There were fewer problems for Mrs Clinton, who defeated her rival Bernie Sanders in Florida, North Carolina, Ohio and Illinois. She also had a slight edge in Missouri, according to vote tallies.
“We are moving closer to securing the Democratic party nomination and winning this election in November,” said Mrs Clinton, casting one eye on the general election - and at Mr Trump.
“When we hear a candidate for president call for rounding up 12 million immigrants, banning all Muslims from entering the United States - when he embraces torture, that doesn’t make him strong. It makes him wrong.”
The scope of Mr Trump’s victory against Senator Rubio in Florida will shock the Republican establishment as much as it will raise hopes the party can challenge in the one-time swing state come November 8.
President Barack Obama carried the state in both the 2008 and 2012 elections.
Senator Rubio bowed out, saying: “While it is not God’s plan that I be president in 2016 or maybe ever, and while today my campaign is suspended, the fact that I’ve even come this far is evidence of how special America truly is.”
Governor Kasich meanwhile openly called for a contested convention and vowed to campaign on.
“I want to remind you, again tonight, that I will not take the low road to the highest office in the land,” he said.
Ted Cruz, an ultra-conservative senator from Texas, also remains in the Republican race.
Projections by US media showed him in a virtual tie with Mr Trump in Missouri, and in second place in Illinois and North Carolina.
Republicans will now have to decide whether to rally behind one candidate or siphon votes away from Trump as a team.
* Agence France-Presse