It was asked: Would a microstate require nukes to be sovereign?
Probably not. Here’s why:
A microstate would aim to fill itself with highly skilled, productive workers who would provide useful services within the international economy. Other segments of the international economy would not want to be severed from a useful partner.
If economic integration isn’t enough, pay tribute. The hard working segment within the American empire today is already paying tribute. The US redistributes money heavily. Part of the appeal of a microstate is the opportunity to separate from those who refuse to work.
If direct tribute to the aggressive polity fails, then bribing leaders within the aggressive polity might succeed.
Up to this point, it has been assumed the microstate is wealthy. An option however is for a microstate to be strong but poor, an attempt at a 21st century Sparta. (Unlike Athens, Sparta guarded against greed within the polity.) Such a neo-Sparta could defend itself, as Switzerland can today; but it would lack the desirable assets that entice aggressive polities into attacking. The cost of attacking neo-Sparta, even if it lacks MAD, should outweigh the gain.
If all else fails, surrender and rejoin the empire, Live to fight another day. It might be possible for a small group to survive, and even to thrive, for a long period within an empire.
The right-wing blogosphere is full of conspiracy theories of rich bankers, the mass media, and international businessmen. If these are some of the great powers of our time, why can’t we strive to use such financial power ourselves? Or if wealth only invites robbery, then spurn the wealth; embrace Spartan virtues!
A negative of nukes is the same as their positive: fear. No one fears Vermont secessionists, because no one, including themselves, believes they’d aspire to obtain, or to even keep preexisting, nukes.
Secession should have a better chance of success if it’s built upon an ideology of disarmament. I use the word “ideology”, because like all ideologies global disarmament is absurd (MAD is part of what prevents war between Russia and the US right now). But a secessionist shouldn’t want nukes for his own polity, and the best justification for such a rejection is an ideology of global disarmament. The weak shouldn’t seek such power, and in a tech race to preserve a MAD balance of power, a small polity will likely lose anyway. So MAD might only be temporary.
It might be said that the wise reject WMD, even when strong enough to pursue them, preferring to instead bend at the whim of each latest temporary superpower as each rises and self-destructs. The microstate bows; but it also survives, outlives the leviathans.