And US part of Mexico.
"And US part of Mexico."
Come on, to conquer a country you need three factors:
1) Superior manpower i.e. numerical supremacy in populations;
2) Superior technologies; and
3) A determined population.
You may say that Mexico has number 3. Well, there are plenty in both Blue and Red states America that are equally determined to stop this to happen. So it is a tie.
Number 1 is obvioualy false. Mexico has only 1/3 of the US's population, and even if you assume "all Mexico-descent Americans are traitors" this still leaves you 40% of the US's population. The US wins hands down.
And number 2? You can forgive number 1 if you have very superior technologies that are used for wars, as the British famously did in 18th/19th century India. Now please wake me up on the day when UNAM (Universidad Nacional Autónoma de México) announces a revolutionary nanotechnology-based handheld size supercomputer replacements. The US once again wins hands down on this point.