Florida and Ohio are hyped up not only because of their favorite sons (for good reason), but also because they are the only “true” winner-take-all states: The Florida winner will claim 99 delegates, and the Ohio winner will claim 66 — no ifs, ands or buts. However, Illinois and Missouri could functionally become winner-take-all too. Both states award their delegates on a congressional-district level. So if Trump (or someone else) sweeps their congressional districts, that candidate will win all the delegates. Together, Missouri and Illinois will award 121 delegates — which would go a long way in helping Trump stay “on track” for the nomination even if he loses either Florida or Ohio.

And so Illinois and Missouri are a big part of the reason Tuesday is such a huge fork in the road. If Trump sweeps Florida, Illinois, Missouri and Ohio, he will have at least 748 delegates and would need to win only 44 percent of all remaining delegates,2 a remarkably low bar, potentially ending the nomination fight.

If Trump loses Ohio but still wins Florida and sweeps Illinois and Missouri, he would need to win 50 percent of all other remaining delegates, a slightly higher bar but still very doable — and he would probably still be “on pace” for the nomination according to our delegate targets. But if Trump were to lose both Ohio and Florida, along with, let’s say, half of Illinois’s and Missouri’s districts, he could find himself needing to win 63 percent of remaining delegates to clinch the nomination, a much less plausible goal, considerably raising the odds of a contested convention in Cleveland.