2. It reminds Mexicans they lost half of their country to the U.S.

Americans often forget that a large part of the United States once belonged to Mexico. But most Mexicans are keenly aware that the United States, eager to expand West, invaded Mexico and the two countries fought a war from 1846 to 1848.

When it was over, Mexico lost half its territory to the United States, including the present-day states of California, Nevada, Utah, Arizona, and parts of Colorado, Wyoming and New Mexico. The war followed the U.S. annexation of Texas.

Trump import tax to pay for Mexican wall would hit American consumers
“I don’t think Mexicans wake up every morning and think about that,” said Francisco Lara-Valencia, a Mexico-born professor at Arizona State University’s School of Transborder Studies.

Still, he sees evidence that Trump’s plan to wall off the entire border is stirring nationalist feelings in Mexico, which led to Peña Nieto’s decision Thursday to cancel his meeting next week with Trump.