When it comes right down to it, though, I don't believe anyone should be afforded citizenship as a birthright. IMO each and every person should have to earn it. You would have certain basic rights as a civilian US resident (and that means paying US income/land/sales taxes, etc), but you would have to earn citizenship in order to vote, and perhaps other rights.
I favor honorable military service but that doesn't have to be the only path. Civil service has many faces. Being a full-time EMT, fireman or police for the same number of years as a military term of service. You could own/operate a business above a specified profit margin for a certain number of years, and/or until a certain level of normal taxes have been paid. Perhaps you become some kind of medical physician, or other trade certified technician, hold residency for a number of years and offer a certain % of your services for free to the poor.
We could play with it any number of ways, so long as it's difficult and beneficial to society.
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Then the other side of it is, once someone's a citizen, let's loosen everything up. Open up marriage to be pretty much whoever wants to do it. Issue a gun-permit all states have to honor and remove all the stupid rules. Take religious symbols out of government buildings and coins, but if folks want to "speak the word" in a public aria, leave them alone.
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If a business uses illegal immigrant labor, they should face devastating consequences, including heavy punitive fines, loss of business license, and felony charges.