There is now fairly broad agreement that Donald Trump can capture the Republican nomination even if he doesn’t quite get to the magic number of 1,237 delegates, as long as he’s close enough. But there’s no clear consensus on what constitutes “close enough.” So I decided to get a firmer sense of that by looking at the key variable: How many delegates will be unbound, or up for grabs, going into the Cleveland convention?

To start, let’s see where the race stands. Following Trump’s crushing victory in New York, he now has 843 delegates who are bound to vote for him on the first ballot. There are 620 bound delegates still to be allocated in remaining contests between now and June 7, and Trump would need to win nearly 64 percent of them to capture the nomination outright. But that’s where the unbound delegates come into play.

Trump has an argument to make to them that the GOP should nominate the person who won the most delegates and popular votes, and that failing to do so would trigger a massive backlash against a system that Trump and his allies have been portraying as “rigged.” Add in promises, personal wooing, and it’s conceivable that Trump could win over some degree of these delegates. But how many will even be available to pitch in the first place?