How Cruz and Kasich could deny Trump the nomination

What happens to the Republicans after Rubio's... 01:45

Donald Trump now has more than half of the delegates he needs to get the Republican nomination. But that isn't stopping his opponents from doing everything they can to stop him.

John Kasich took home his winner-take-all state of Ohio, which gets the party closer to a contested convention.

"Not winning those 66 delegates in Ohio means Trump has to do better in the future," said "Face the Nation" anchor John Dickerson. "Now he needs to win 52 percent of the remaining delegates up for grabs."

Dickerson on Trump's momentum, where Rubio's ... 02:43

So what do Kasich and Ted Cruz have to do in order to have a shot at the nomination?

"They have to win enough delegates to deny [Trump] the majority," Dickerson said. "But that's going to be hard to do because Kasich and Cruz keep splitting the non-Trump vote."

As for Marco Rubio's demise after losing his home state of Florida, Dickerson says he was "selling the wrong product." Voters this year don't seem to want optimism, but someone who shares their anger.

To hear what else Dickerson had to say about the Republican race, watch the video above.