As soon as it became clear that game-show host Donald Trump was the presumptive Republican nominee, the usual radio ranters and Fox News mouths began the inevitable litany: If you aren’t for Donald Trump, then you must be for Hillary Clinton — it’s Himself or Herself.

There is more to this than A/B testing.

“If you aren’t for Trump, then you’re for Clinton” is a cheap rhetorical ploy. I’d write that any thinking adult would be ashamed for falling for that kind of sixth-grade debater’s stratagem, but a Republican electorate capable of choosing Donald Trump as its standard-bearer is incapable of shame.

The angry insistence — him or her! — is, for the moment, mainly an attempt to forestall further criticism of Trump. That criticism consists of stating a fact that is not a matter of degree but a binary proposition, a yes/no question. It is not that Trump is less mentally stable than Mrs. Clinton (probably true) or that he is more dishonest than Mrs. Clinton (difficult to say) or that he might do even more damage to the republic, or any other point of comparison between the candidates.