"It's not clear that it's going to decide the election, the nominees. But it could. If Mr. Trump and the Republican Party sweeps it, he will, I think, be impossible to deny. His momentum will be overwhelming. On the other hand, should he lose Ohio or lose Missouri, or both, I think it would suggest that there's going to be a long, long fight here," Ciruli said.
If Rubio doesn't win in Florida, and Gov. Kasich doesn't win in Ohio, neither candidates would have a chance, according to Ciruli.
It's a similar situation on the democratic side, where both Hillary Clinton and Bernie Sanders are hoping for some victories Tuesday night.
"If Hillary Clinton could win a sweep here, I think the race would pretty much be over," Ciruli said. "But Bernie Sanders would stay in it. He would argue that there are other states he might win. But it would be very, very clear that her march is inevitable to get the nomination."
Florida and Ohio are valuable because the delegates up for grabs in both of those states are winner take all. Ciruli predicts that the race for the nomination on both sides of the aisle isn't going to be over any time soon.
"My sense is that this isn't going to be one of those years in which people just quit ... In normal years, by this point, certainly after tonight [Tuesday], if many of these candidates lost, they would quit," Ciruli said. "Both limitations of money and simply the party would say, 'you had your shot, you didn't win.' This is not one of those years. Everybody seems to want to keep going.”