Ted Cruz may have a tough day on March 15.

Five states are in play: Florida (99 delegates), Illinois (69), Missouri (52), North Carolina (72) and Ohio (62).

There have been fourteen open primaries so far—contests in which Democrats and/or Independents are allowed to vote for the Republican presidential nominee. Donald Trump has won eleven of these races. Marco Rubio has won two, Minnesota and Puerto Rico. Cruz has won only one, his native Texas.

Without question, Democrats have given Trump his lead in the Republican race.

Three of the Republican races are open to Democratic voters on March 15: Illinois, Missouri, and Ohio.

North Carolina is unique that day. Its primary is considered to be a hybrid of open and closed primaries. Independents, but not Democrats, can vote for the Republican nominee. Its delegates will be apportioned to the candidates proportionately according to the votes received.

Everyone is focusing on Florida, Rubio’s home state, and Ohio, where John Kasich appears to be ahead. Florida, a closed primary, is winner-take-all. Rubio appears to be losing there, but Michigan proved the inaccuracy of primary polling.

Let’s not forget Illinois, where the Chicago Tribune projects Trump to be the winner. Missouri is anyone’s guess.  A Cruz win there would have to be considered an upset given Trump’s record in open primary states.

But even if Trump sweeps every state but Ohio on March 15, there is hope for the Cruz camp. Few open primaries remain. Marco Rubio would have to bow out.

Then let’s see what happens when Trump faces Cruz where only Republicans can vote. A lot of the remaining primaries are winner-take-all. It’s a long way to the magic number of 1237 delegates. California, with 172 winner-take-all delegates, may be the key race.

As Yogi Berra said, “It ain’t over til it’s over.”