The eye naturally travels to the picture first, an edited photo showing a small-headed Jeb Bush standing outside Trump Tower holding a cardboard sign on which "VOTE TRUMP" is written. The gag itself doesn't make much sense; why would Bush be telling people to vote Trump? And couldn't his well-heeled Right to Rise super PAC put up the cash for a nicer placard?

Then, you notice whose tweet Donald Trump was retweeting: @WhiteGenocideTM. "White genocide."

This Twitter user, whose profile page says his name is "Donald Trumpovitz" and that he lives in "Jewmerica," has a series of tweets espousing racist or Nazi-sympathetic views and sharing anti-Semitic photos and news stories. He or she also regularly tweets racist things in response to Trump's tweets, with the obvious hope of being seen by other people who are viewing Trump's tweets or getting a retweet from Trump himself.

Here's a response from @WhiteGenocideTM to a tweet a few hours ago.

(Notice the use of "cuckservative" in that image. We looked at that newly crafted insult last summer, including its racial undertones.)

The expression "white genocide" is commonly used by white supremacy groups as a way of suggesting that white people in the United States are under threat by virtue of shifting demographics or, more recently, political correctness. Trump's campaign has been embraced by white supremacists for its focus on deporting undocumented immigrants and barring Muslims from entering the country. Earlier this month, a prominent white supremacist produced a robocall endorsing Trump that was sent to voters in Iowa.

Trump's Twitter account has had a few controversial and racially loaded moments. There was the time he tweeted a picture that included a swastika. The time he retweeted deliberately misleading numbers on blacks and violence. The time an official campaign image included German soldiers.

And, of course, the time he insulted Iowans via retweet, questioning whether GMOs had addled their brains as Ben Carson gained in polling in the state. After that one, Trump's Twitter account apologized. "The young intern who accidentally did a Retweet apologizes," he wrote.

We asked the campaign for comment on this incident. We have not yet heard back.

Update: Trump deleted a tweet since the @WhiteGenocideTM one -- but it was a tweet that didn't express enough enthusiasm about poll numbers he wanted to share. The original version, as captured by our automatic candidate tweet collector:

And the final version:

Update 3:00 p.m.: @WhiteGenocideTM protected his (or her) tweets briefly, which had the unfortunate-for-Trump side effect of making his tweet look worse, not better.

But they're available again, for better or worse.