There are already so many illegals here in Calif that when you cross the border into Baja, it doesn't even seem that different any more. Especially between TJ and Rosarito - it's a mini-Orange County in the making. (The housing tracts & retail sections look identical to Irvine.) With so many Americans buying up property, the demographics look just like OC: rich whites/Asians living in nice houses and Hispanic laborers providing the muscle.
Mexico is what is referred to in finance as an 'under-valued asset'. At a purely intrinsic level, it is worth way more than Canada. As it stands, they have a screwed up legal/property/capital system that seriously restricts their growth opportunties. With US legal systems, it would create the world's largest boom market.
The temporary downside would be millions of Dem voters; however, this would only be a short-term issue before capitalism converted their previously indolent country into a mirror of the US. Forget Aztlan; we'll be seeing the descendent of illegals agitating for annexation in a few generation's time.
Best advice ever, make the Mexican states, states in the US, abolish the direct election of senators, and we'll be in business.
Either that or asset forfeiture for employers who employ illegal aliens.
A non-starter.