Mexico has often wanted to destroy the United States.
The relationship typically has been poor, but Mexico was never forced to fight for its existence and the United States has been overwhelmingly powerful.
Many Mexicans never gave up the belief that Mexico rightfully owns the Southwestern United States.
Many Mexicans, Central and South Americans believe they have a birthright ownership entitlement to at least the Southwest by virtue of being genetically closer to the Southwest Native Americans than the completely unrelated white colonizers.
A sizable portion of these "refugees" and "immigrants" believe in the Reconquista where they will forcibly take back the Southwest from the United States and or the white settlers once their numbers and power are great enough.
This would or will destroy the United States.