The current immigration policy is fine. Quotas should be increased though. And it isn't just Mexicans who emmigrate here. Think of all the asians, europeans, arabs, africans, and latin americans (oh, and those pesky canucks! ) who come to these shores every year. If we raised the quota, but also adjusted our policy to enforce some sort of aclimation program, we could greatly reduce "culture-shock" for both the current citizens and the immigrants, and greatly reduce and/or eliminate the illegal immigration problem.
Oh, "Nativisim" and the US are a special issue with me. We are all in the great melting pot of the world. The US is the most integrated and diverse society on Earth, bar none. For those of you who were lucky enough to have been born here, try not to be so xenophobic. From immigration does the United States receive some of its best minds, and some of the most patriotic people. My experience has shown me that a naturalized citizen takes the US more seriously than does someone who was just born here. Hell, the head of the Joint Chiefs of Staff was a Polish immigrant I believe (I can't quote for sure what his nationality was). Can't get much more patriotic than that.
Count your blessings. In many places of this world, people are born with few. To many impoverished and persecuted people in the world, the US still shines as the land of opportunity. It is the people who were born here who have gotten lazy, and take it for granted. The fact that so many people want to come here is a good thing.
My $.02. Consider yourself enlightened.