This has been going on a long time.
The Reconquista ("reconquest") is a term to describe an irredentist vision by different individuals, groups, and/or nations that the Southwestern United States should be politically or culturally returned to Mexico. Known as advocating a Greater Mexico
On February 6, 1998, the Mexican consul general in California, Jose Angel Pescador Osuna, spoke at the Southwestern School of Law in Los Angeles as part of a symposium on the 1848 Treaty of Guadalupe Hidalgo, which gave the Southwest to the United States. Osuna proclaimed, “And even though I am saying this part serious, part joking, I think we are practicing La Reconquista in California.”
But he was only admitting what has been a policy of the Mexican government for more than three decades: Surplus people are encouraged to immigrate, legally or illegally, to the United States, California in particular, and to maintain their Mexican identity and loyalty.
Wrote Mola:
A peaceful mass of people, hardworking, carries out slowly and patiently an unstoppable invasion, the most important in human history. You cannot give me a similar example of such a large migrator,’ wave by an ant-like multitude. Stubborn, unarmed, and carried on in the face of the most powerful and best-armed nation on earth. The result of this migration is to return the land to the jurisdiction of Mexico without the firing of a single shot.
https://chroniclesmagazine.org/correspondence/the-reconquista-of-california/