In the months since President Donald Trump won on Election Day, Trump has continued his unusual habit of questioning the legitimacy of his own election — claiming that he would have won the popular vote if “millions of people” hadn’t voted illegally, and now calling for an investigation into voter fraud, even though reputable studies have found voter fraud is nearly nonexistent in the US.

What’s the basis for all of this? A new report by Glenn Thrush for the New York Times suggests it might have started with a story from a “friend” that may or may not be true, which Trump retold to congressional leaders on Monday:

Mr. [Bernhard] Langer, a 59-year-old native of Bavaria, Germany — a winner of the Masters twice and of more than 100 events on major professional golf tours around the world — was standing in line at a polling place near his home in Florida on Election Day, the president explained, when an official informed Mr. Langer he would not be able to vote. Ahead of and behind Mr. Langer were voters who did not look as if they should be allowed to vote, Mr. Trump said, according to the staff members — but they were nonetheless permitted to cast provisional ballots. The president threw out the names of Latin American countries that the voters might have come from. Mr. Langer, whom he described as a supporter, left feeling frustrated, according to a version of events later contradicted by a White House official.

One catch: None of this may have happened. Langer’s daughter told the Times that he is not a US citizen, so he can’t vote. She added, “He is not a friend of President Trump’s, and I don’t know why he would talk about him.” (Langer was apparently too busy to talk with the Times directly.) Furthermore, an anonymous White House aide told the Times that Langer may have been talking about something that happened to a friend of his rather than to him personally.

Langer later said in a statement that he never shared the story with Trump. Instead, he heard the story from a friend, retold the story to another friend, and then that friend shared it with someone with ties to the White House:

Statement from Bernhard Langer on what amounts to a game of telephone re: voter fraud story with Trump: pic.twitter.com/Z9ClQvPvOq — Will Gray (@WillGrayGC) January 26, 2017

Still, Trump’s retelling of story is revealing. For one, it shows just how Trump’s mind works. As the Times puts it, the story is “a memorable example” of how Trump’s “fact-gathering owes more to the oral tradition than the written word.” This is a polite way of saying that Trump is apparently moved more by what people tell him — even if it’s completely unverified — than he is by actual news articles and research.

But a certain part of Trump’s story also speaks to how people are discriminated against in the polling booth. As Trump reportedly put it, the only reason the man in the story believed that those few voters at the front of the line shouldn’t have voted is because they didn’t look the part and may have come from an unspecified Latin American country.

In other words, Latino people are suspicious in the voting booth, while it’s outrageous that a white man like Langer couldn’t vote. (The fact that the white man in the story may not even legally be allowed to vote is the cherry on top here.)

This biased perception is why measures like modern voter IDs and old polling taxes — which were used to keep black voters away from polling places during the Jim Crow era — can be in effect racist even if in theory they aren’t.

If a white person is presumed to be allowed to vote, a polling place may not bother to ask him for voter ID.

But if a black or brown person faces greater suspicion of ineligibility, he’s going to be asked for an ID more often. And since black or brown people are already less likely to have flexible work hours or own cars often required to get to the DMV and get an ID, they might be less likely to have that ID and be able to vote when asked for it.

There’s evidence to back this up: A study for the Black Youth Project, which analyzed 2012 voting data for people ages 18 to 29, found 72.9 percent of young black voters and 60.8 percent of young Hispanic voters were asked for IDs to vote, compared with 50.8 percent of young white voters.

The anecdote, then, isn’t just telling about how Trump’s mind works when approaching policy issues. It also helps expose a big problem with the voter ID laws that he supports.

Watch: 6 ways your voting rights could be violated on Election Day