I remember the fall of communist Romania.
It could be very swift. If the US is bankrupt, VERY swift.
Don’t the that monitory bankruptcy will be the problem, it will be the government that eventually causes the collapse though inflation (intentional). Of course the money side will be an indirect cause.
Also don’t think that it will be so swift... much longer time frame but much more devastating to the population, especially those on limited incomes.
Allowed to go long run - mayor riots, car burning (see France), looting, massive unrest. Get a gun!