miner wrote:So, mon ami, have there been any attempts at secession within the USA since the American Civil War (which was, after all, 150 years ago)?
For example, the Alaskan Independence Party has been a factor in state politics for some time, and a member of that party, Walter Hickel, was Governor from 1990 to 1994. There have been various moves for Californian independence, including some last year. The Georgian State Senate has passed resolutions that include the right to declare the US Constitution nullified under certain circumstances. Texas would seem to have the strongest claim to be able to secede, given that it was an independent republic before acceding to the Union. There's even been moves for Washington, Oregon, and the Canadian province of British Columbia to secede and form a new state of Cascadia.
None of these attempts have been successful. Despite being large, ethnically-diverse and in many respects somewhat cobbled-together, the US is one of the world's most stable countries. There's no reason to suppose that unions are inherently unstable: look at Russia, Germany, India, Brazil, Australia and the Netherlands, for example. The Union of Soviet Socialist Republics fell apart, but the Russian Soviet Federated Socialist Republic carried on in business as the Russian Federation. Yugoslavia fell apart but Germany was reunited. Sudan broke up but Yemen was unified. Malaysia seems to be doing pretty well for itself despite the secession of Singapore.
And looser groupings of states can survive for considerable periods: in the case of the Holy Roman Empire, in many respects the first EU, for nearly a millennium.
It is (genuinely) a pity you have not studied more history. It would have given you a much broader view.