The Great Depression fed dangerous new autocratic ideologies like fascism and communism; a second Great Depression could destroy them. While the economic crisis will cause untold human suffering in these and other countries, it is quite possible that, on the other side of it, we will see the end of that distinctive phenomenon of the late 1990s and early 21st century: the growth autocracy. And that, at least, would bring some light to a financial dark age.
While it is difficult not to be happy with this possible development, remember that the autocracies may not go down willingly. Will such regimes seek to bolster their stability by provoking a foreign conflict?
And nuclear-armed regimes in a death throe could be particularly dangerous.