As tensions run boil over the presidential-campaign trail, Donald Trump could be just days away from effectively locking up the Republican presidential nomination.

Wins next week in Florida and Ohio — the two largest winner-take-all states in terms of delegates — would be what he called the “knockout” on CNN last Wednesday, two days before he canceled a Chicago rally amid mass protests.

“I think if I win those two I think it’s over,” Trump said. “I think if I win Ohio and I win Florida you’ll be pretty much assured.”

He continued: “If you knock them out, nothing can happen. I’d rather go for a knockout.”

Even Trump’s biggest critics agree. Florida GOP consultant Rick Wilson told Business Insider that Trump would be unstoppable after winning the two states.

“If Trump wins both Ohio and Florida, the seventh seal has opened and the apocalypse has begun,” Wilson said. “The Four Horsemen ride into the land to destroy us all.”

John Green, the chair of the political science department at the University of Akron, didn’t quite share Wilson’s despair. But he did say Trump’s assessment of the race was accurate.

“I don’t find myself agreeing with Donald Trump very often about politics,” Green told Business Insider. “But when he said on Wednesday that he thought [the coming Tuesday] would be a decisive day, I think there’s a good bit of truth to that.”

The two wins would give Trump all 165 delegates, even if they were secured through weak statewide pluralities. Trump would then significantly increase the already nearly 100-delegate gap between himself and Sen. Ted Cruz of Texas.

Although Cruz is closest to Trump in delegates, Cruz’s chances on beating the frontrunner could easily depend on the other two GOP candidates — Sen. Marco Rubio of Florida and Ohio Gov. John Kasich — besting Trump in their respective home states Tuesday.

For Rubio, it appears to be an uphill battle in the Sunshine State. He trailed Trump by roughly 15 points in the RealClearPolitics average of at least 11 polls released this week. The most recent poll suggested that Rubio was gaining ground, but no recent polls have shown him ahead of Trump.

Rubio began to call for strategic voting on Friday, insisting that a vote for any candidate other than himself in Florida is essentially vote for Trump.

The senator said that Kasich is “the only one who can beat Donald Trump in Ohio,” and added, “If a voter in Ohio is motivated by stopping Donald Trump, I suspect that’s the only choice they can make.”

But Kasich isn’t returning the favour to Rubio.

“We were going to win in Ohio without his help, just as he’s going to lose in Florida without ours,” Kasich campaign spokesman Rob Nichols told Politico.

That confidence came from Kasich’s tighter battle with Trump in his home state. In Ohio, Kasich trailed Trump by just 2.5 points in the RealClearPolitics average of recent polls. Nichols also told Business Insider that Kasich had an “undefeated” and lengthy electoral record in the state.

“We’re not going to lose Ohio, we’re fine,” Nichols said. “We’re not going to lose Ohio, and Trump will have to go elsewhere.”

Nichols also predicted that Kasich’s fortunes would increase, especially if Rubio hits a wall in Florida.

“This is playing out very, very well for us,” Nichols said. “What other guy on the stage has a single accomplishment other than personal wealth?” he asked.

Green said he believed that Kasich will end up winning Ohio by a slight margin because of his organisation within the state. But Green also said he’s astonished the race is so close there.

“If you would have told me that, 18 months ago, Ohio would have a contested primary at all — with an Ohio governor running for president — I would have laughed at you,” Green said.

Over the past few days, Trump’s campaign has shifted over the past few days go after Kasich much harder. On Friday, Trump released an attack ad against Kasich and criticised him as “absentee” at a campaign rally. On Saturday, the mogul scheduled two more rallies in Ohio.

Despite the escalating attacks, Kasich has yet to win a state and has the lowest delegate total of the four remaining GOP candidates. And Kasich’s path to the nomination is cloudy at best even if he wins his home state.

“There is no path for Kasich right now no matter what,” said Wilson, the GOP strategist. “I mean, everybody’s saying, ‘Marco drop out Marco drop out.’ And John Kasich is not being asked every 30 seconds, ‘Why don’t you drop out?’ is ridiculous.”

At Thursday’s CNN debate, Kasich suggested that — like Rubio — his plan would be to win the nomination through a contested convention, in which no candidate enters with an outright majority of the delegates.

“Frankly, I don’t know if we’re going to get a convention like that,” Kasich said of the possibility. “But if we do, I was at one in 1976 as a wee lad and supported Ronald Reagan and actually worked directly with him. He tried valiantly. He lost. Gerald Ford won. The party was united.”

But even if Rubio and Kasich both win their home states next week, the battle to stop Trump would be far from over. In a FiveThirtyEight article published Friday, David Wasserman crunched the numbers and concluded that other crucial states will also weigh in next Tuesday.

Wasserman wrote:

March 15 has long looked like the most pivotal date on the GOP primary calendar. And although Florida and Ohio are hogging the spotlight because they are the sites of Marco Rubio and John Kasich’s “last stands,” don’t forget that two other states could help Donald Trump become essentially unstoppable in his quest for the nomination: Illinois and Missouri.

“Together, Missouri and Illinois will award 121 delegates — which would go a long way in helping Trump stay ‘on track’ for the nomination,” he added, “even if he loses either Florida or Ohio.”

Follow Business Insider Australia on Facebook, Twitter, and LinkedIn