Trump ran against something like 10 serious candidates, because the new campaign finance rules encouraged everybody with a rich buddy to run, and all of them scrambled for the same airtime and the same voters, while Trump’s shameful appeal to intolerance, along with his TV and Twitter celebrity, landed him a modest plurality of unshakable voters.

It wasn’t until deep into the primaries, with his nomination a foregone conclusion, that Trump finally managed to sway a majority of Republicans to his side. He didn’t storm the fractured party establishment; he outlasted it.

The math looks very different when you’re running against only one candidate from the start, or even two. An enraged, nativist 30 percent won’t get it done.

The traditional Republican electorate, rallied behind a single challenger in the name of restoring dignity and greatness to the party, might create a surprisingly strong counterforce to the dwindling audiences at Trump’s rollicking rallies.