Sam Wang of the Princeton Election Consortium has looked at the allocation systems for the early Republican states and figures that, for Trump not to win the nomination, one of two things needs to happen quickly: Either he needs to stumble badly, or a bunch of his opponents need to drop out.

The problem for the non-Trumps is that the system is working against them. After South Carolina, the big contests on Super Tuesday (March 1) and March 15 will distribute delegates proportionally. The winner gets more delegates than the losers, but the losers get something.

As Wang notes, though, it’s not a 1-to-1 ratio. The winner often gets proportionally more delegates than those further down in the rankings; according to Wang’s models, winning 30 percent of the vote through March 1 would yield 50 percent of the delegates. That’s in part because candidates receiving too low a percentage of the vote would get no delegates at all.

By the time March 15 rolls around — less than a month from now, we would note — nearly half of the total available delegates will have been allocated. After March 15, that number jumps to more than 60 percent. There are a lot of contests between now and then, but if the overall dynamic doesn’t change — a Trump lead with other candidates trailing — Trump will have banked a lot of delegates.