It probably seemed like a good idea at the time. The National Association of Black Journalists extended an invitation to Donald Trump to appear at their convention, creating an opportunity for the organization to raise its visibility, and offering NABJ professionals an opportunity to hear directly from a man who might soon become president.

The Republican nominee, meanwhile, accepted the invitation, hoping to reach an audience beyond his far-right base.

What could possibly go wrong?

Before the former president even took the stage, problems emerged. As my MSNBC colleague Ja’han Jones explained, “The organization faced a deluge of denunciations from journalists and activists after it announced it would give a platform to Trump, who has denigrated the free press, spread racist propaganda and repeatedly insulted Black journalists. In fact, NABJ has issued several statements in recent years denouncing Trump’s illiberal behavior and attacks on its members.”

But after the GOP nominee actually started speaking, Trump not only made matters far worse, he also validated the concerns of those who warned the NABJ that it was making a mistake by giving him a platform in the first place. NBC News reported:

Donald Trump made a combative appearance Wednesday at a conference of Black journalists during a heated question-and-answer session that at times focused squarely on the race of Vice President Kamala Harris. Trump claimed that he did not know until a few years ago that Harris, who is Indian American and Black, was Black. He then baselessly suggested that she had decided to “turn Black” only recently for political gain.

To be sure, Trump’s appearance at the convention was a train wreck for a variety of reasons. His rhetoric about “Black jobs,” for example, was a mess. He similarly went out of his way to be as insulting and condescending as possible to some of the Black women who asked him good and fair questions. As is usually the case, he also lied — a lot — about matters large and small.

But it was Trump’s comments about Harris’ race and ethnicity that were jaw-dropping.

“I’ve known her a long time, indirectly,” Trump said, referring to the Democratic vice president. “And she was always of Indian heritage, and she was only promoting Indian heritage. I did not know she was Black until a number of years ago when she happened to turn Black, and now she wants to be known as Black.”

In case that wasn’t quite enough, the Republican added, “I respect either one, but she obviously doesn’t, because she was Indian all the way, and then all of a sudden, she made a turn and … she became Black. … Somebody should look into that, too.” Trump concluded, “Is she Indian or is she Black?”

The unscripted comments were obviously racist. They were also sadly predictable given Trump’s lengthy record of overt racism. What’s more, as a New York Times analysis added, “The audacity of Mr. Trump, a white man, questioning how much a Black woman truly belongs to Black America was particularly incendiary. … [I]t evoked an ugly history in this country, in which white America has often declared the racial categories that define citizens, and sought to determine who gets to call themselves what.”

The idea that Harris — who is both Indian American and Black — could have a multifaceted racial and ethnic background is apparently intolerable to the Republican candidate. Trump expects voters to believe that the vice president “happened to turn Black,” which is every bit as wrong and offensive as it seems.

Team Trump developed a plan to go after the likely Democratic nominee. Having Trump question Harris’ identity, while insisting that she “obviously” doesn’t “respect” her Indian and Black heritage, was not part of that plan. Indeed, it didn’t come as too big of a surprise when the former president’s aides pulled the plug on the appearance and Trump left the stage before the end of his scheduled appearance — though he continued to go after Harris’ identity in the hours that followed the event.

In a normal and healthy political environment, in a normal and healthy political party, this was the sort of appearance that might very well end a candidacy.

The larger question isn’t whether Trump is relying on racism — again — to advance his quest for power, because the answer is obvious. Rather, the question is why in the world would he put on this racist display while appearing at the National Association of Black Journalists’ convention.

Let’s not forget that for much of the year, the Republican and his team seemed determined to improve their showing with Black voters. What’s more, there was some polling evidence that suggested those efforts were paying off, and Trump was poised to fare better in communities of color in 2024 than any other modern GOP nominee.

But if that was a priority for Team Trump when it was facing President Joe Biden, it’s no longer a priority now. What the public saw at Wednesday’s event was a candidate who had a plan for reaching out to Black voters, and then set that plan on fire.

In fact, it’s easy to believe that those in attendance at the NABJ event were not the intended audience at all. As The Washington Post’s Colbert I. King summarized in his latest column, “As offensive as all that was to the Black men and women staring in his direction, Trump knew it was getting a belly laugh with his crowd, who can’t get enough of that stuff.”

Common sense suggests Trump did not earn any support on Wednesday from communities of color, but by all appearances, they weren’t the intended audience for his offensive antics.