You just never know. OK, at least seven in 10 Republicans approve of Trump, whatever that really means. That’s marginally impressive.

Except that we don’t know what those voters would do when faced with an actual choice — not between Trump and Democrats, or Trump and the media, but between Trump and a thoughtful conservative who doesn’t tweet insults in the middle of the night.

We don’t know how Trump would fare with Republicans in a field of two (or three), rather than in a field of 17, where all the more established candidates fractured their vote into tiny shards last time around.

We don’t know what Trump is going to say or do in the intervening months, or on the eve of the primaries, that could tip the balance very quickly toward a Republican alternative.

And we don’t know yet where independent voters are going, especially in New Hampshire, where they make up the largest bloc and can vote in primaries. In 2000, John McCain beat out Bill Bradley, a Democrat, for most of those votes, transforming him into a genuine threat to George W. Bush.