I've been thinking about this topic for a while, and haven't ever really thought up a good way to frame it. So instead I'll just throw out my thoughts and see what comes back.
As some of you may know, my wife and I are seriously considering moving outside the US in the relatively near future (~5 years or less, most likely). The detailed timeline and reasons are largely unimportant, but we are certainly keenly interested in making the big move. What's somewhat odd, though, is how we will continue to interact with the US as American citizens, and how we should.
Plenty of ex-pats vote in US elections, carefully register their children for US passports, and frequently have significant assets parked in the US (along with major investments in US debt and equities). They self-identify as American in ways that cannot be easily divorced from their worldview and outlook. Yet I wonder - if I legitimately have chosen to live the rest of my life outside the US, do I have a right to call myself an American?
Now, this could easily degenerate into an argument about the semantics of who defines an American. But let's just look at practical matters: Should we continue to vote in US elections? If so, should we vote with an eye to improving our own situation (e.g. candidates who would be friendly to our country of residence, or pass tax laws that would help us), or should we vote for a hypothetical 'domestic' electorate? Do we have the moral right to vote, anyways?
What about taking advantage of the protections afforded US citizens, both for us and our children? Should we travel under US passports and go to US embassies or consulates in times of trouble? Is it fair to do so when we have effectively repudiated the US as our home, but still cynically take advantage of the privileges of citizenship?
On an even stickier question - should we vote in our adoptive country in a pro-US manner, or just choose candidates that are best for the country itself?
I guess this is an issue that has been troubling me for some time. There are a lot of ex-pats from various developed countries floating around, and I'm not sure the traditional model of immigration is followed in their cases. There is rarely a repudiation of their country of origin or a whole-hearted embrace of their new home, but at the same time their motives can get awfully messy from an ethical perspective. I have no doubt I will always have a quintessentially American worldview, and will always wish the very best for the country in which I was born. To be honest, life would be a lot easier if we just stayed in the US with a fairly wealthy lifestyle, and we will always have a strong fondness and connection to the US. Yet I don't know if that connection should give me the same rights as someone who actually lives in the US. What are the ethical obligations of citizenship, and the ethical prerequisites to exercise the rights of citizenship? How can dual-citizenship be managed in today's globalized setting?