And how naive an adult could be. The birther imaginings about Barack Obama? Just a silly conspiracy theory, latched onto by an attention seeker who has a peculiar penchant for them. The “Mexican” Judge Gonzalo P. Curiel incident? Asinine, inappropriate, a terrible attack on the judiciary by an egocentric man who imagined that the judge didn’t like him. The white supremacists’ march in Charlottesville? The president’s comments were absolutely idiotic, but he couldn’t possibly have been referring to those self-described Nazis as “good people”; in his sloppy, inarticulate way, he was referring to both sides of the debate over Civil War statues, and venting his anger about being criticized.

No, I thought, President Trump was boorish, dim-witted, inarticulate, incoherent, narcissistic and insensitive. He’s a pathetic bully but an equal-opportunity bully — in his uniquely crass and crude manner, he’ll attack anyone he thinks is critical of him. No matter how much I found him ultimately unfit, I still gave him the benefit of the doubt about being a racist. No matter how much I came to dislike him, I didn’t want to think that the president of the United States is a racial bigot.

But Sunday left no doubt. Naivete, resentment and outright racism, roiled in a toxic mix, have given us a racist president. Trump could have used vile slurs, including the vilest of them all, and the intent and effect would have been no less clear. Telling four non-white members of Congress — American citizens all, three natural-born — to “go back” to the “countries” they “originally came from”? That’s racist to the core. It doesn’t matter what these representatives are for or against — and there’s plenty to criticize them for — it’s beyond the bounds of human decency. For anyone, not least a president.