“There’s a set of people who are true believers that Donald Trump won the election and is going to be inaugurated, but that’s a relatively small set,” he said. “There’s also a small set of people who acknowledge Joe Biden won, but not nearly as many as you would hope.

“And there’s a lot of people who are at different degrees of acceptance in between.”

In that group, political scientists say there are also people who give the equivalent of the party line answer to survey takers, regardless of their real beliefs.

“The evidence is strong that a number of people out there, even if they know the truth, will give a cheerleading answer,” said Seth Hill, a political scientist at the University of California, San Diego. Part of the president’s base appears eager to stick it to the establishment, he said. If those voters interpret surveys about the election’s legitimacy as part of that establishment, he said, “it’s quite possible they will use this as another vehicle to express that sentiment.”