Thanks to Rubio’s withdrawal, Kasich should be able to challenge Trump more effectively in blue-state primaries beginning with the Wisconsin primary on April 5.
If Rubio voters rally behind Kasich in Wisconsin, the governor could score another significant victory over the front-runner in the coming weeks. Neither Kasich nor Cruz will be able to win the nomination outright before the convention. However, by depriving the front-runner of wins in Ohio and maybe Wisconsin, Kasich can make it extremely difficult if not impossible for Trump to secure the needed majority of delegates in time. Kasich may also be able to get the better of Trump in other Rust Belt states that vote later in the spring. Rubio may have been unable to stop Trump as a candidate, but by getting out of the race he has given Kasich the chance to do just that.
Kasich won in Ohio by six points, and as I said in this piece he is now the strongest competition for Trump among somewhat conservative and moderate Republican voters. The best thing Rubio could do for the anti-Trump cause was to get out of the race. That has arguably been the case for weeks, but it is certainly true now. Despite some last-minute talk about staying in the race after tonight, Rubio was right to accept defeat and leave the anti-Trump effort to Kasich and Cruz.