With Marco Rubio out and Donald Trump still winning big, there’s only one real way the GOP will keep the nomination from Trump.

Here are the three remaining Republican candidates and their delegate counts, keeping in mind that 1,237 delegates gives you the nomination: 522 for Trump, 395 for Ted Cruz and 138 for John Kasich. Trump picked up Florida’s 99 delegates but none of Ohio’s 66, which went to Kasich. Now, there’s no mathematical way for Kasich to get 1,237 delegates, so let’s put him aside for the moment. Cruz theoretically could hit that number, but he’d have to win about eight out of 10 voters in the rest of the race. Doesn’t look like that’s going to happen.

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But here’s why Ohio was so important Tuesday, even with the fact that Kasich has already been mathematically eliminated.

By winning there, Kasich has deprived Trump of a big boost toward that magic delegate number. Now Trump needs 669 delegates to clinch the nomination. And there are 909 delegates still up for grabs in the GOP race.

Let’s assume Trump wins 46 percent of those delegates, just as he’s won 46 percent of delegates so far. That would give Trump 418 more delegates — not enough to clinch the nomination.

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And even that is probably pretty generous toward Trump. After all, most Rubio supporters listed Cruz or Kasich as second choices. So what happens if no candidate reaches the target delegate number?

We get a brokered convention, meaning voting could go to a second ballot where a lot of delegates are free to vote for whomever they want — not necessarily how their state voted. And that could ultimately decide the GOP nominee.

Over the next few weeks and months we’ll see the Cruz campaign and others lobby those delegates hard and do their best to charm them away from Trump.