As a permanent resident alien of the US, I'm not too thrilled about where this thread is going.
To clear up a few things...
As part of the immigration process...applicants are screened. Police and health records must be provided. Heck, if you can't come up with your childhood innoculation records...they will give you a horse needle with vaccinations to everything...again.
In the case of family petitions, the person claiming you must vouch for your financial welfare, since you are not allowed any federal (not sure if state) assistance.
Once you are approved and come to the US, you are bound by all the laws of the land and the obligations that come with it (important since it iS April 17th). And with very small limitations (ability to hold some offices, vote and participate in juries)...you enjoy the same rights.
Unless your screw up...and get yourself deported, you can be a permanent legal alien for as long as you like. After 5 years of being a green card holder you can opt to become a US Citizen (after passing a simple citizenship test).
It's not easy to become a permanent legal alien in the US. I had to wait 14 years for my petition's number to come up. But this is a very good country in which to live in so many people choose to do so (as did I). Others do so out of necessity (not so much my case).
In any case, I appreciate the fact that we are allowed to live in this great country enjoying the same rights as those who were born here. It would really be nice if it stayed that way.