Being good (self-reliant, kind, knowledgable, hard-working) makes you American. Not whether you were born here (country of origin, ethnicity, etc.). This is what immigration policy should be screening for. Some of the best people I know are immigrants.
"You can go to live in France, but you can't become a Frenchman. You can go to live in Germany, Turkey, or Japan, but you can't become a German, a Turk, or a Japanese. But anyone, from any corner of the earth, come to America and be an American." - Reagan in '98