Any institution can fail at any time, given the right trigger. The difference between a stable institution and an unstable one is the range of triggers that wil

Any institution can fail at any time, given the right trigger. The difference between a stable institution and an unstable one is the range of triggers that will destabilize it. When the legitimacy of an institution is threatened, this can only broaden that range. So you're right to point out that there is no "threshold" as stated by the OP, however the frenzy with which the US government is undermining its own legitimacy as well as that of many other Western governments, does not bode well for our civilization (Western or otherwise).