But even in that Monmouth poll there were signs that his virtual campaign has yet to instill passion in crucial parts of his coalition. Among liberal voters, 33 percent said they were less enthusiastic than usual about voting in this year’s election. Voter enthusiasm ran higher among conservatives; just 12 percent of those voters said they were less enthusiastic than in previous years.

The CNN poll painted a similar picture, but more starkly: Four in five Republican voters said they were quite enthusiastic about voting this year; just 56 percent of Democratic voters said the same.

Of course, it is still early to draw definitive conclusions from these numbers: Mr. Trump has been in office for over three years, and he continues to address the public in news conferences multiple times a week, while Mr. Biden’s general-election campaign has hardly gotten off the ground. That is precisely what worries some Democratic observers.