When Republican presidential nominee Donald Trump pays a spontaneous visit to Mexican president Enrique Peña Nieto on Wednesday, they're going to have a hard time avoiding the elephant in the room: Trump's famous proposal to "build a wall and make Mexico pay for it."

Perhaps, though, Peña Nieto might come to the meeting armed with a counterproposal: one that Mexican Twitter users have been suggesting for ages. It would even allow Donald Trump to make his planned immigration speech in Phoenix Wednesday night without having to go through customs first.

APOYEMOS A DONALD TRUMP. SI AL MURO FRONTERIZO pic.twitter.com/NeFyYrR3pS — sixto jesús (@sixtodlp) August 20, 2015

The text reads (translated figuratively):

WE SUPPORT DONALD TRUMP: YES TO THE BORDER WALL

//

WE'LL HAPPILY SEND YOU THE PLANS, AND DON'T WORRY, MEXICO WILL PAY FOR IT. WHEN WILL THE PRE-CONSTRUCTION EVICTIONS START?

The point, of course (to belabor the joke), is that the US-Mexico border that Donald Trump and others treat as inviolable has actually shifted substantially over time — and the very places where Americans today are most liable to imagine an "invasion" of immigrants in fact belonged to Mexico long before they ever belonged to America.

Back when Americans were invading Mexico

Because the meme goes all the way back to when Mexico was still a colony of Spain, though, it actually misses the point when Mexico really could have used a wall. This is what the US-Mexico border looked like in 1826, a few years after Mexico won its independence from Spain:

You'll notice that "New Mexico" is still part of original Mexico. So are Arizona, California, and, crucially, Texas.

You might recall the story of how Texas joined the US from history class, depending on how willing your teacher was to let historical Americans look like jerks. But think about it from the perspective of "border security" as we know it today, and it's literally the mirror image of everything the most paranoid white Americans fear about Latino immigrants.

When this map was drawn, Texas (which, again, was part of Mexico at this time) was being invaded by a wave of immigrants from the US. These immigrants brought their foreign cultural values with them, including the ownership of slaves. And they didn't respect the rule of law: When Mexico tried to ban slavery, the immigrant slaveowners found a way to get around it.

Mexico responded by trying to step up border security: In 1830, it banned US immigration into Texas, and started enforcing customs at the border. The immigrants responded by rioting, and released a set of demands including reopening the borders and independence.

Ultimately, the immigrants raised an army. Because so many of them had immigrated, they were able to beat the Mexican Army and declare themselves an independent nation in 1836. When Mexico continued to dispute (militarily) the extent and size of the newly independent Republic of Texas, the United States annexed Texas, declaring it to be a part of America — thanks to a resolution that specifically upheld the backward cultural value of slave ownership.

What would have happened if Mexico had, from the beginning, taken "border security" as seriously as the US does today (much less as seriously as Donald Trump wants the US to take it)? Would the stigmatization of American immigrants have continued to make the immigrants feel more American than Mexican, just as immigration experts worry stigma against Latino immigrants impedes their integration today?

Or could Mexico have saved itself defeat in two different wars by building a wall on the US-Mexico border back when the "invasion" began?

Donald Trump likes to say that "If you don't have borders, you don't have a country." One can almost picture Mexican President Antonio López de Santa Anna going "Ay, tell me about it!"

The Arizona dynamic: white newcomers freaking out about Latino long-timers

All of this is just an elaboration on a line that Latinos in the American Southwest often use: "We didn't cross the border, the border crossed us." That's true for the US population of Mexican descent as a whole, though it's often not true of individual families (many of whom arrived in the US long after it had officially become the US).

But even many of the Latinos whose families arrived in the Southwest after it became part of the United States have been residents of the region for much longer than many of the white people who are freaking out about immigration.

That's the other irony of the border region: It's been shaped by two different waves of immigrants. It's just that one of them has gone unnoticed because it's migration that's taken place within the United States, and because the immigrants are white.

Journalist Bryan Curtis pointed this out in a Daily Beast column in 2010, when Arizona was in the throes of controversy about its immigration-crackdown bill (known as Senate Bill 1070), championed by then-Gov. Jan Brewer:

Senate Bill 1070 is often seen as an outgrowth of Mexican migration. But Arizona has a parallel migration narrative: one of Anglo migrants who came for the hot weather and golf courses, and, in many cases, brought along their conservative politics. Evan Mecham, the governor who canceled the state’s Martin Luther King holiday in 1987, was an arriviste from Utah. John McCain didn’t make it to Phoenix until he was in his 40s. Jan Brewer, a California native, relocated to the Phoenix suburbs with her husband, a chiropractor, in the 1970s. So Brewer’s blasts are, in one sense, correct. Arizona has suffered an "invasion."

If only Mexico had built a wall to begin with, none of this conflict and trauma would ever have occurred. Perhaps it even could've gotten the US to pay for it.