To be clear I specifically didn’t say “a few demonstrations.” :) In a scenario like this, it might start with people in government, including the military, not following orders.

A lawyer friend shared this example with me of a Supreme Court justice ordering the Nixon administration to stop bombing Cambodia. They were quickly overturned by other justices, but in that short time, the Air Force didn’t necessarily follow the letter of the law. https://en.wikipedia.org/wiki/William_O._Douglas (see section on Vietnam War).