That's only the half of it. It would not just produce heartburn, it would destroy our constitutional freedoms, because Mexico and Latin Americ have proven for two or three hundred years that they cannot govern themselves without endless cycles of tyranny, revolution, and lawlessness.
If enough illegals pour into this country, they will accomplish the same thing here. You cannot have freedom without respect for the law and a minimum of self-control. Freedom cannot be imposed.
Ahem, it would expedite the already promoted destruction of our constitutional freedoms.
Better?