I don't know why we don't help Mexico. They are currently experiencing tons of killings related to the drug trade and some innocent people are getting caught in the crossfire. This isn't giant warring factions like we're dealing with in the Mideast, this is relatively small groups of "guns for hire" fighting skirmishes for drug lords. I guess we can't impose our will in a country that doesn't want our help; but isn't that what we're doing overseas?
It just seems to make more sense to me to help Mexico get on it's feet than to spend our money keeping everyone out. If Mexico gets better, people won't want to leave. In the meantime our friends with Mexican heritage can't visit their relatives and the the country continues to plunge into lawlessness. Mexico is a beautiful country with a rich heritage and culture. The Mexican people have so much to offer the rest of the world. I don't know why we continuously ignore our closest neighbor.
If it's truly our "manifest destiny" to spread democracy around the world, I would think fine tuning the democracies that are in place but defective should come first.