The nut of the problem isn't U.S. policy, enforcement, or the lack thereof, although I agree that the current policy is outdated and not properly enforced because politicians on both sides are terrified of their fringe constituencies. The real problem is that Mexico is basically a failed state. It has incredible natural resources and a population that is generally willing to work much harder for much less compensation than Americans. But government corruption, drug cartels, an ongoing small war in the northern states, and an economy that has been in the tank for decades drives the more enterprising or desperate Mexicans north--Green card or no Green card. Until Mexico gets its act together the U.S. is going to have an immigration problem regardless of what our government does. Which gives me an idea for another thread...