WASHINGTON — You know a politician is having a bad week when he spends it trying to convince people he’s too unsophisticated to have possibly understood the racial slur he tossed at a man who happened to be armed with a video camera.Sen. George Allen’s mental journey to the imaginary land of Macaca has brought the one-term Virginia Republican — considered a presidential hopeful for 2008 — more national attention than ever before. But not in a good way.

The Macaca incident became a sensation on the video-sharing Web site YouTube.com, where some visitors helpfully posted clips of macaques, which are monkeys. It spawned a host of predictable jokes — “Funny, you don’t look Macacan” — and inspired a hilarious bit on “The Daily Show” that ended with a potty-humor punch line not entirely suitable for the opinion pages of a distinguished newspaper. Suffice it to say that another make-believe realm called Yapipi was invoked.

As you probably know by now, Allen was making a campaign stop and spotted a college student who was shadowing him — videotaping all his appearances — to gather possible ammunition for the campaign of his opponent, Democrat James Webb. The young man, S.R. Sidarth, is of Indian descent. Allen pointed him out for the all-white crowd, calling him “Macaca, or whatever his name is”, and then said to Sidarth, “Welcome to America and the real world of Virginia”. Sidarth happens to have be a Virginia native.

Allen and his aides scrambled to assure reporters that the senator had no idea that macaca is the genus to which macaques belong. Nor did the senator have a clue that in some European countries “makak” is a derogatory term for North African immigrants.

OK, I’m willing to believe the senator is ignorant of primate taxonomy and Belgian slang — he’s all about good-ol’-boy bonhomie, not Renaissance-man erudition. I don’t buy the rest of his explanation, though — that he was trying to refer to Sidarth’s haircut, which he thought was a mohawk. I also don’t buy his claim that he meant no offence.

I think he was playing to the crowd by singling out the one person who didn’t belong there, not because he was a spy from a rival campaign — shadowing is standard campaign practice these days — but because he looked “foreign” (my word, not his). I think he came up with “Macaca” as a kind of generic name for a foreigner who appeared to be from the Indian subcontinent, or someplace over there where people have dark skin and straight black hair. Why else would he add the “welcome to America” bit, if not to emphasise Sidarth’s apparent foreignness?

Let’s assume for the moment that the Macaca moment was not premeditated, that it was an ad lib. That means Allen instinctively or subconsciously believed that drawing a line between his white audience and the darker, foreign-looking Sidarth was, at that moment, good politics. It was a way of defining “us” and “them,” and the thing is that it worked, drawing a hearty laugh from the crowd.

If the senator doesn’t realise that Americans come in an increasing range of shapes, sizes and colours, then his ignorance extends far beyond Old World monkeys and obscure slurs. Surely he has seen the new census figures that show how immigrants are settling in parts of the country that traditionally have had little or no foreign-born population. Maybe that was the point.

If we are to accept the testimony of friends who insist that Allen himself is no racist — I’ve met him but only briefly, so all I can report is that he seems genial enough — then maybe the Macaca thing didn’t grow out of ignorance at all, but out of a sense that there is political advantage to be had from playing on fears and apprehensions about immigration. Maybe he was giving that audience in conservative southwestern Virginia a clear message: I’m with you, I’m one of you, and we all understand that the guy over there with the camera is not one of us, he’s just a Macaca whose real name probably has a lot of awkward syllables and isn’t worth learning to pronounce.

Because of his swagger and personality, Allen is often likened to George W. Bush. The president, for all his manifold faults, is one of the few politicians who really does understand the changing face of America. I’m beginning to think that perhaps Allen understands it too — at least well enough to know what buttons to push among white audiences.

Senator, I don’t think you’re as ignorant as you claim.Eugene Robinson’s e-mail address is eugenerobinson[AT]washpost.com.