(CNN) What exactly did President Donald Trump mean by "breeding" when he tweeted Wednesday about cities that will not cooperate with the federal government to deport the undocumented.

This is Donald Trump. He meant exactly what you think.

The tweet, offered Wednesday morning, argued that Californians prefer his hard-line policies to those of Gov. Jerry Brown.

"There is a Revolution going on in California. Soooo many Sanctuary areas want OUT of this ridiculous, crime infested & breeding concept. Jerry Brown is trying to back out of the National Guard at the Border, but the people of the State are not happy. Want Security & Safety NOW!"

There is a Revolution going on in California. Soooo many Sanctuary areas want OUT of this ridiculous, crime infested & breeding concept. Jerry Brown is trying to back out of the National Guard at the Border, but the people of the State are not happy. Want Security & Safety NOW!

It is true that the government of Orange County has voted twice now to opt out of the state's so-called "sanctuary" law.

Whether there is full-blown "Revolution" in California seems less likely.

But it's the next part of the tweet that is more difficult to understand.

"Sooo many Sanctuary areas want OUT of this ridiculous, crime infested & breeding concept," according to the President.

There is great danger in trying to dissect every word of a Trump tweet, but in this case it is worth trying to figure out. CNN has reached out to the White House to figure out exactly what he meant.

The tweet has not been deleted at the time of this writing, so he means for those words to remain out there. In other words, it's not likely to be at typo. He has been known to correct those in the past.

A simple Google search doesn't uncover any specific mention of a "breeding concept" with regard to sanctuary cities in the conservative media, so it's a little unclear what he's referring to.

Taken literally, the most likely explanation is that he's talking about sanctuary cities as places where undocumented immigrants breed.

If that's right, there's a racial undertone in the comment should slap you in the face.

Fear of immigrants from certain countries "breeding" has been a staple of nativist thought for hundreds of years. The "breeding" fear has been affixed to Jews from Eastern Europe, Catholics from Ireland and Italy, Chinese and, now, Latinos, Filipinos, Africans and Haitians. This is dog-whistle politics at its worst.

"Breeding" as a concept has an animalistic connotation. Dogs and horses are bred. So his use of it is, at best, dehumanizing to the immigrants he appears to be referring to.

The other possible definition of the word has to do with manners passed down through generations. In that case, Trump is saying people in sanctuary cities weren't raised right. That doesn't seem to work within the context of the tweet.

Plus, there is Trump's obsession with the idea of immigrants flooding the US. He's insisted that immigration reform end the concept of what opponents call "chain migration."

"Under the current broken system, a single immigrant can bring in virtually unlimited numbers of distant relatives," Trump said during his State of the Union address. Politifact called that claim " misleading ."

At the outset of his presidential campaign, he seemed intent on challenging the 14th Amendment's guarantee of birthright citizenship.

"What happens is they're in Mexico, they're going to have a baby, they move over here for a couple of days, they have the baby," he told Fox News in August 2015 as he was taking command of the Republican field. "Many lawyers are saying that's not the way it is in terms of this," and went on to say, "They are saying it is not going to hold up in court. It will have to be tested but they say it will not hold up in court."

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In an interview around the same time with CNN's Chris Cuomo, he said, "You have people on the border and in one day, they walk over and have a baby and now all of the sudden, we're supposed to pay the baby."

Changing interpretation of the 14th Amendment is not an issue he's pursued as President, but it's clear from those early interviews that he has at times wanted to pursue it and that he's been nervous about immigrant children.

More recently, he's raised concerns that immigrant women coming into the US have, in large numbers, been raped.

All of those things put together suggest Trump's "breeding concept" tweet, consciously or not, is in line with his efforts use ever more divisive rhetoric on immigration.