Just buy the damn thing. Make it the 51st state of the union.
And they will all vote republican. And more than pay for their social costs.
I think that's exactly what is happening. Governments from both US and Mexico are working hard to remove barriers to annexation.
Lot's of money to be made in building Mexico's infrastructure. Mexico is rich in natural resources and available labor. Annexation is the long-term plan to save Social Security.