Why not let them all in? But tag each & every one in some definitive manner. Anyone caught here without the 'tag' does not go back home, they go to prison for a year or two and then send them back. Anyone who's more than a minor nuisance or becomes chronically unproductive, send them back. If they're still here.. 10.. 15.. years later, allow them a means of naturalizing. This is (as so many things are in my mind) an individual thing; there's no tagging along because you're related. The USA isn't forcing you to split up your family, you are, you could always stay put.
Which reminds me, we may choose to let you all come here. But that doesn't mean you have any kind of 'right' to immigrate. In all likelihood, USA citizens can't simply move permanently into your country, what the hell makes you think you can simply walk into ours? And since your country is your country, I have no objection to you keeping us out if you want to. Accept that we've got the same right to pick & choose who we let in.
I have no trouble with this tagging/ID thing - they're not citizens, they accept our terms or they stay out. And if none are being denied entry, why refuse?
Most of them are what we saw during the peak migration years of the early 1900s - decent productive people with some ambition to better themselves. So why wouldn't we want them? The huge majority of the 'bad guys' are your routine crooks, thugs, and lay-abouts and you can pretty much count on them to blow it sometime during their 10 or 20 year wait and get their asses sent back where they came from. Yes, probably there will be a very very few really really bad people who could be part of a long-term sleeper cell situation, but they may prove easier to locate once they're inside this country than outside. And sadly, no matter what you do, you won't find 100% anyway.
Now the big downside of all this is jobs for current citizens. The unfortunate truth is that our fellow citizens are already competing against these potential immigrants; it's probably to our advantage that they're here working for $7.25 minimum wage rather than there in their native country working for $1.50. And the still harsher truth - we would be getting their best, brightest, most ambitious, most motivated which makes them better for our country in the long term than the citizens they might displace. And I certainly hope we'd have provisions for citizens displaced from their work (although that is certainly a whole other issue).
edit: I see this is pretty damn close to my previous note on this topic. I guess I'm getting pretty close to a position.
