Without the ability to conceive of anything that is both plausible and dangerous, it's best to wish them well.
Marcus and Michele Bachmann are Swiss citizens. Press reports circulated this week to the effect that they'd just obtained that status. Bachmann subsequently issued a statement asserting that she's actually been a dual citizen of the U.S. and Switzerland since 1978.
National Review's Mark Krikorian is as unhappy about this as can be. "It's not that they're giving up American citizenship and moving to Switzerland, which is their right, if the Swiss permit it -- rather, they're acquiring dual citizenship. This is outrageous and she needs to hear about it," he wrote (operating on the earlier, apparently faulty presumption that they just changed their status). "Dual citizenship isn't simply a matter of convenience, a way to make travel easier or a sentimental tie to the Auld Sod. It's a formal declaration of divided allegiance, civic bigamy, if you will."
People obviously have have multiple connections -- church memberships, community groups, fraternities, ethnic associations, professional societies, etc. But one's chief political allegiance is expressed through citizenship, through being a member of We the People -- and claiming membership in two national communities is like belonging to two different religions, which means neither is accorded the respect due it.
And if you still aren't convinced:
If you're not going to join with them as a permanent member of their national community, destined to share in both their triumphs and their struggles, then don't pretend to be Swiss -- it's an insult to both countries. And there is no justification for such a thing when we demand that foreigners seeking to become Americans take an oath that reads, in part: "I absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state or sovereignty, of whom or which I have heretofore been a subject or citizen." As John Fonte has written, "Dual allegiance is incompatible with the moral basis of American constitutional democracy." The fact that even a patriot like Bachmann would do something like this is testament to how thoroughly the moral relativism of the post-national Left has permeated our culture.
I'm not convinced. This is partly because Krikorian doesn't include any specific, practical problems that could ensue if Bachmann and her husband stay the course. Are there any? If I had to guess, this is in fact "a matter of convenience," "a way to make travel easier," and "a sentimental tie to the Auld Sod." If the Swiss are okay with that, why shouldn't I be? Would America be better off if the Bachmanns felt whatever they currently feel for Switzerland, but didn't have citizenship there? This way if war comes with the Swiss we can make them pick sides!
In 1792, French citizenship was bestowed upon George Washington, Alexander Hamilton, and James Madison. Thomas Paine served in the French National Convention. Countless immigrants who lack dual citizenship nevertheless maintain a powerful attachment to the land of their birth. And some Americans with dual citizenship don't feel any particular patriotic loyalty to the country where they wanted to work or own property or retire. All of which is to say that it's a mistake to conflate the legal status of citizen, patriotic attachment, and depth of civic loyalty (and absurd to write as if this issue is someone caused by "moral relativism" or "the post-national left.")
Perhaps dual citizenship obtained by Americans in large enough numbers would be a problem. But my best guess is that the Bachmann family's Swiss citizenship will have literally no impact on America. I'd nevertheless be happy if there were a way in international law for people to designate a second country in which they want to travel easily, work without inconvenience, and signal affection. I pick Spain.