That so many Republicans nonetheless shook them off is about as vivid an illustration as you’ll find of the peculiar and chilling nature of partisanship today. But the picture is more complicated and fuzzier than that.

For starters, when these polls were taken, it’s entirely possible that what happened in Helsinki hadn’t sunk in. Most people don’t pay nearly as much attention to the Trump melodrama as those of us lashed to it do, and as we map the confluence of his misdeeds and their moods, we routinely discount the degree to which many of them are tuned out. They have more pleasant things to do than monitor this president. Laundry, for example. Hemorrhoid surgery.

On top of which, the volume and velocity of his offenses turn them into a blur, just as the alarms that we in the media sound become white noise. This was true during his campaign, it’s even truer of his presidency, and it’s one of the most unjust, infuriating aspects of his endurance. His shamelessness is actually his saving grace.

But not with everyone, and most notably not with some aghast Republicans who, thanks to Trump’s takeover of the party, have strayed from it. There’s a fascinating debate about how much the Republican loyalty to Trump in poll after poll is skewed by an exodus of former Republicans whom he scared off. They may not be showing up as party members in surveys, and Trump’s high marks could be coming from a winnowed, favorable sample.

Brendan Nyhan examined this possibility in The Times’s Upshot section last year, describing data that suggested that “people who identify as Republican may stop doing so if they disapprove of Trump, creating a false stability in his partisan approval numbers.” If those people were factored back in, according to this analysis, Trump’s partisan approval rating could dip to 70 percent.