Adding to what Amos says, I think it's a logical fallacy to ascribe moral strictures to the breaking of laws. This is a very American thing that has been drilled into many of us since childhood - to think that people who break laws are bad people, and thus are not morally suitable to become American citizens. I get this from my talk-show-addicted mother-in-law all the time, about how it's morally wrong break the immigration laws.
Well, I think it's very important for us to remember that morality and legislation are two different things. Things that are immoral are harmful or unjust. Things that are illegal are simple failures to obey the mandate of the legislature. Sometimes criminal and moral law can coincide, but oftentimes criminal and civil law are simply arbitrary.
It is rarely a moral wrong to immigrate, even if the immigration is illegal. Sometimes, it's the immigrations laws themselves that are immoral, and I think that the US has a long history of immorally discriminatory immigration law.

-Joe-