Who is right about Rubio — Trump or Cruz?

After Marco Rubio’s poor showing yesterday, Donald Trump called on the Florida Senator to drop out of the race. Meanwhile, as Eliana Johnson reports, Ted Cruz seems to be ramping up his campaign in Florida, where polls show him to be a distant third. His efforts seem likely to help Trump win and thus to drive Rubio out of the race.

Apparently, Trump and Cruz both believe they will benefit from a Rubio exit. They both can’t be right. Who is?

Not long ago, the conventional wisdom (which I subscribed to) was that to stop Trump, the field needed to be reduced to two candidates — Trump and another. Recently, as Trump began to seem nearly unbeatable, the thinking changed. Now, a bigger field is considered desirable in order to deprive Trump of as many delegates as possible, with the hope of blocking him at the convention.

Yet, Cruz, whose campaign is said to employ world-class data analysts and game theorists, apparently wants to knock Rubio out. He seems not to buy the the “more the merrier” theory.

One can easily understand why Team Cruz might see things this way. Take last night. It’s quite possible that only Marco Rubio stood between Cruz and a sweep of all four contests.

Cruz finished second in Louisiana and Kentucky, only about 4 percentage points behind Trump. Rubio won about 16 percent of the vote in Kentucky and 11 percent in Louisiana. Absent Rubio, Cruz probably would have won Kentucky and might have carried Louisiana.

As long as delegates are being shared, Rubio’s “spoiler” impact isn’t significant. But once we get to the winner-take-all stage, it’s potentially devastating to Cruz.

Things aren’t quite that simple, though. Kentucky and Louisiana are one thing; Pennsylvania and Wisconsin (say) are another. Cruz hasn’t shown that he is competitive in states like the latter two.

But if Trump is stalling, with a ceiling of, say, 40 percent, then Cruz might realistically think he could win two-way races against Trump — and maybe even a three way race (with John Kasich) as the third man — in the North and industrial Midwest states. After all, Rick Santorum nearly won a few such states in 2012 before the party coalesced around Mitt Romney.

In any event, it’s difficult to see Rubio winning, or piling up many delegates, in states like these (though perhaps he could if a Florida victory revives his campaign). Even in non-winner-take-all states, the main effect of Rubio’s candidacy might be to pick off delegates that would have gone to Cruz or Kasich, and/or to prevent Cruz or Kasich from getting to the threshold they need to win delegates.

If so, then Rubio’s continued run seems inconsistent with a “block Trump” strategy and is certainly inconsistent with a “someone other than Trump wins outright” approach.

In a sense, Florida could be a win-win for the anti-Trump forces. If Rubio loses, maybe he drops out, which probably helps Cruz for the reasons stated above. If Rubio wins, Trump is deprived of around 100 delegates, thus promoting the “block Trump” strategy, and the “Trump is stalled” narrative takes hold.