It is by no means clear even that staunch Marco Rubio supporters should want Ted Cruz out of the 2016 presidential race.

It is now conventional wisdom that the best way for Republicans to avoid nominating Donald Trump is to have all but one other candidate drop out of the presidential race—and the sooner, the better. Then the anti-Trump vote can consolidate into that remaining candidate.

Conventional wisdom also holds that, among the three leading candidates—Trump, Ted Cruz, and Marco Rubio—Cruz is the one who should exit (or at least fade into irrelevance), as Rubio is the candidate with the best chance to consolidate the anti-Trump vote.

This conventional wisdom, however, appears to be wrong. Regardless of who might ultimately prevail as the GOP nominee, the party’s best shot of stopping Trump seems to be having a strong Cruz competing in the contest.

The main flaw in the conventional wisdom is that it’s based on an unduly optimistic assessment of Rubio’s chances of beating Trump head-to-head. So far, Rubio has an uninspiring medal haul of two silvers and one bronze (to Trump’s three golds and a silver, and Cruz’s gold and three bronzes).

Yes, this is partly because Jeb Bush, John Kasich, and Chris Christie have gotten a lot of potential Rubio votes. Still, to date, Rubio, Bush, Kasich, and Christie have received only a combined 38 percent of the vote. Trump, Cruz, Ben Carson, and Rand Paul have received a combined 60 percent (with the remaining 2 percent split among other candidates).

Cruz Competes Better against Trump

Trump himself has gotten 33 percent of the vote to date. To win an outright majority from this point forward, he would need to win only 37 percent of the non-Trump, non-Rubio vote. Rubio, meanwhile, would have to win 63 percent of the non-Trump, non-Rubio vote. Having to win more than five-eighths of that vote, while Trump needs less than three-eighths, would be a big challenge for Rubio—a challenge compounded by the fact that most (57 percent) of the non-Trump, non-Rubio vote to date has gone to Cruz or Carson. Does anyone really think that, among current Cruz and Carson supporters, Rubio would completely dominate Trump?

Does anyone really think that, among current Cruz and Carson supporters, Rubio would completely dominate Trump?

Even in an imaginary world in which Cruz—who so far has won more votes, more states (one to zero), and the same number of delegates as Rubio—Kasich, and Carson all went “poof” and immediately disappeared from the race, Rubio’s prospects would hardly look great. In that scenario, say Rubio could get the votes of 60 percent of Cruz and Carson supporters (perhaps an optimistic tally) while Trump got the remaining 40 percent. Rubio would still need to get the votes of more than two-thirds (68 percent) of the other candidates’ supporters to start outpacing Trump from that point forward.

That would be possible, but certainly not easy. Keep in mind that, among the one-sixth of South Carolina voters who called themselves “moderate”—that’s the group with which Bush and Kasich, in combination, did the best—Trump beat Rubio by 11 points (34 to 23 percent).

Immigration Makes Rubio’s Path Harder

Moreover, the difficulty of Rubio’s task in a two-man race would be compounded by two things: One, he hasn’t yet shown he can go toe-to-toe with Trump, as each has avoided the other. Two, Trump and Rubio represent something close to the party’s two poles on the important issue of immigration, and the center of the party is likely nearer to Trump.

Trump and Rubio represent something close to the party’s two poles on the important issue of immigration, and the center of the party is likely nearer to Trump.

Some supporters of a loose immigration policy viewed the results of the South Carolina exit polling—which found that 53 percent of Republican voters would give illegal-immigrant workers a path to legal status, while 44 percent would deport them—as suggesting that most Republicans are with them on this issue. In truth, those results showed the opposite and made Rubio’s challenge appear all the more daunting.

First off, the question asked only about illegal immigrants who are working in the U.S., not illegal immigrants generally. Second, the 53 percent didn’t want to grant them eventual citizenship, which is Rubio’s position, but rather “a chance to apply for legal status.” Third, the answer most people would presumably prefer to give for illegal immigrants who are working—leave them alone but don’t give them legal status—wasn’t even provided. Fourth, when given a choice between making them legal or booting them out of the country, almost as many people said they’d send them packing as would let them stay. That does not bode well for Rubio.

Indeed, the prospect of having the candidate who is most like Chris Christie in manner take dead aim at Rubio for his wildly unpopular (among GOP voters) efforts on this issue should not make the Republican establishment feel confident of victory.

Rubio Should Help Cruz Tank Trump

Then again, this would be the same Republican establishment that helped fuel Trump’s candidacy in the first place (by refusing to fight on much of anything or heed Main Street concerns), assured everyone that Trump wasn’t a serious threat, and now thinks the only thing needed to beat Trump is to get Cruz (and Kasich) out of the race.

Far more so than with Trump and Rubio, Trump and Cruz are competing for the same voters.

Rather than rooting for the establishment’s preferred scenario, those who would like to avoid a Trump nomination would presumably be better off hoping for another result. A more plausible scenario for beating Trump would be to have Cruz remain in the race and have him perform well.

Far more so than with Trump and Rubio, Trump and Cruz are competing for the same voters. If Cruz can pry some of those voters away from Trump, especially by emphasizing more effectively than he has to date how a Cruz presidency would undo much, if not most, of the Obama presidency—thereby portraying himself, rather than Trump, as the agent of change—that would help not only Cruz but also likely Rubio.

If Cruz also, with some overdue help from Rubio, could knock Trump down a peg or two, to where he is no longer claiming a third of the vote, then the Donald presumably wouldn’t become the nominee. In that scenario, Rubio or Cruz would prevail by June, or else the result would be decided at the convention.

In short, it is by no means clear even that staunch Rubio supporters should want Cruz out of the race. Better to have Cruz battle Trump, have Rubio finally start to train some of his fire on Trump, and let the best man win in a three-way contest.