I don't think its possible to say that "staying is morally superior" OR that "leaving is morally superior," as if the answer were the same for everyone in all circumstances. There were many who left Jerusalem, and Judea, and were scattered, but some stayed.
If I had been living in the days of the Massachusetts Bay (not Plymouth) or one of the other Colonies, I might well have been inclined to leave for the new world. I'm sure it felt "worth it" for the sake of pure worship and for the sake of children. That being said, I don't think that one has to participate fully in the world, when they choose to stay.
For example, as beneficial as it might be as a pastor, to put my kids in a public school--in a small-town environment, to "be a part" of the community and build ties--there have to be better ways, if that school is a part of a larger system that actively attacks the Christian faith, if those teachers and administrators (however good their intentions) are bound by the terms of their employment to deny God, and if real discipline is absent.
So, is there really "no place" to go, anymore? I used to think so, until I stopped thinking like an American. Think about it: the early Colonists had similar thoughts. "How can I leave England, for someplace worse in so many ways?" They decided it was worth it, for a vision of what that frontier could become. And more, they transplanted "England" (New England) with themselves.
So, ask yourself if you are truly in love with principles and ideals, or simply the America of your youth, or your grandparents? There was a lot less freedom then, than at the beginning. When most people say "The US is the best/freest/greatest nation," etc., they usually mean that America has the highest standard of living that they know of. This, they reason, must be because we are so free. So, in other lands, the people must be generally poorer because they are oppressed. But that isn't always the case.
The other major reason why "we're the greatest," is attributed to the prevalence of the rule of law. But if federalism is dead, and the Constitution subverted, are we really under "the rule of law" or not? Or is that just another one of those slogans? If they want to, they can take away your property--eminent domain means whatever those in charge want it to mean. Right to life? Not after Roe v. Wade--privacy, a non-right, has been place over a right spelled out in plain text.
Are we a nation of law? LAWS, yes, enough to make us all lawbreakers every day, whether you know it or not. But not LAW, in the sense of fixed standards, "discovered" as it was once explained, or "derived" from continuity and conversation with the past. The LAW has been rendered wholly positive, and it means in the end, what 5 Supremes say it means.
So, if we are "freer", it is because there are residual echoes of the fixed standard. Those are fading like ripples in the pond. We are very close to the time when Caesar's word will make law once again. Even your RonPaulRevolution is likely nothing but a milepost on the way to despotism. Even if elected, his term would most likely mark the end of the American Experiment. "He stood for what it stood for at the beginning, like a bookend."
So, may I suggest that whether you stay or go, you should have in mind the Kingdom of God and Christ, to which you belong. You can follow the increasing dictates of tyranny here, or go abroad in search of greater freedoms, but also greater responsibilities. You might go as an official missionary, or as one of those "scattered abroad," a private citizen.
But in either case, you can let that little "subversive" inside you out. Go ahead, be defiant! No, I don't mean don't bother to get a Driver's License, or car insurance, not any of that kind of defiance. Far from it. No, I mean you can be involved in taking down Satan's order everywhere it is established. Take a stand for your true King, and suddenly you will find yourself freer than you ever have been. Even if you lose your life. And maybe your children and grandchildren will live in an earthly society that has felt the impact of godliness--if the King holds off in returning.