Roots Of Ilegal Immigration

With all the talk of illegal immigration, few are talking about its roots. Could it have something to do with the fact that many Mexicans are so impoverished?
Clearly, the US should do more to lift the Mexican people out of poverty. It could do so through more just trading laws, more foreign aid and more pressure on the Mexican government to make fundamental reforms.
Certainly, the US could stand to tighten it borders. There are indeed some legitimate national security concerns here.
But, getting, that is only part of the equation. What we really need is a "Marshall Plan" for Mexico which world, in the end, benefit both countries.
Another complication is the fact that about fourteen million Illegal immigrants now reside in the US. So, are we going to deport them all?
That would be a logistical nightmare.
One ansewer would be to give Mexican illegal a one time only amnesty and then tighten up the borders.