As a result, it will be difficult on Super Tuesday for Mr. Trump to amass a significant majority of delegates if the other two major candidates — Mr. Rubio and Ted Cruz — clear the thresholds (at highest 20 percent) for earning proportional delegates. It seemed quite possible a few weeks ago that Mr. Trump could build a big lead on Super Tuesday, but Jeb Bush’s exit from the race and the big bump in Mr. Rubio’s poll numbers make it far less likely that Mr. Trump can pull that off.

Imagine, for a moment, that the candidates fare about as well on Super Tuesday as they have through the first four contests. Given the types of states in play on Super Tuesday, perhaps that yields something like a 34-25-25 percent split between Mr. Trump, Mr. Rubio and Mr. Cruz.

In this scenario, Mr. Trump claims a clear edge in delegate accumulation but not a majority. He gets 279 delegates, or just 44 percent of the delegates at stake, while Mr. Rubio receives 164 delegates.

It’s a respectable tally for Mr. Rubio, even though he loses every state. That’s because he clears 20 percent in every state. That scenario includes Texas, where the most delegates are at stake on Super Tuesday and where Mr. Rubio is in the most danger of missing the delegate threshold because of Mr. Cruz’s home-state popularity. For anyone counting delegates, whether Mr. Rubio reaches 20 percent in Texas is a lot more important than anything else.