Mr. Trump’s claims may appear to his opponents to have been embarrassingly debunked. But social science research suggests that Mr. Trump’s alternative version of reality may appeal to his supporters.

Partisan polarization is now so extreme in the United States that it affects the way that people consume and understand information — the facts they believe, and what events they think are important. The wiretapping allegations could well become part of a partisan narrative that is too powerful to be dispelled.

Mr. Trump, perhaps unconsciously, has grasped a core truth of modern politics: that voters tend to seek out information that fits the story they want to believe, usually one in which members of the other party are the bad guys.

Since the 1980s, Americans have been reporting increasingly negative opinions about the opposing party. Partisanship, and particularly “negative partisanship,” the rejection of the opposing party, has now become a kind of tribal identity that shapes how people define themselves and others, according to Sean Westwood, a professor at Dartmouth College who has studied partisan polarization. “It drives people to support their team at any cost, and oppose the opposing team at any cost,” he said.

This partisan polarization affects the way Americans of all political stripes consume information. People are more likely to believe stories that come from their side of the political divide, particularly if an authority figure vouches for them. And they are more likely to share news with their preferred slant as a way of showing they are good members of their political tribe.

Mr. Trump’s wiretap claim is particularly likely to appeal to that partisan dynamic. At its core, it is a story about Barack Obama being fundamentally untrustworthy, perhaps even dangerous to the country. Mr. Trump’s supporters, who are already more likely to believe that basic narrative, may be more likely to accept his wiretap claims.