The Republican insider told me that internal GOP polls show Cruz with zero crossover appeal to Democrats and swing voters. And a massive national survey by the media and technology company Morning Consult shows that, were the general election held today, Cruz would win even fewer electoral college votes than Trump. Nevertheless, for GOP elites, nominating Cruz offers two advantages. First, he’d bring conservatives to the polls, which could help vulnerable Republicans running for Congress. Imperiled congressional Republicans might not be thrilled to have Cruz atop the ticket, but they could at least endorse him, something many might not do if the nominee were Trump.

Second, and more important, a Cruz defeat at the hands of Clinton this November leaves the GOP in a better position to rebuild than a Trump loss to Clinton does. By conventional standards, Trump isn’t all that conservative. That means, if Trump loses this fall, conservative purists can again make the argument they made after John McCain and Mitt Romney lost: The GOP needs to nominate a true believer. And they’ll have such a true believer waiting in the wings as the early front-runner in 2020: Ted Cruz. After all, losing the nomination to Trump would put Cruz in second place, and the GOP has a history of giving second-place finishers the nomination the next time around (Bob Dole, McCain, Romney). Plus, after building the best grassroots network of all the 2016 candidates, Cruz—who’ll be barely 50 years old in four years—would enter 2020 with a big organizational edge. Thus, the GOP would remain at the mercy of its extreme base.

By contrast, if Cruz wins the nomination and then loses badly to Clinton, his presidential ambitions are likely over. The GOP hasn’t nominated a candidate who previously won the nomination since Richard Nixon in 1968, and Cruz’s 2016 loss will likely be far bigger than Nixon’s in 1960. Moreover, a Cruz loss in November would undercut the right’s argument against choosing a more moderate nominee.