Strike
If a group goes on strike, the worst thing they can do is announce an end date/time. That directly weakens their authority by immeasurable amounts.
Imagine airport workers going on strike indefinitely. That would cripple a city's (and potentially a country's) economy. Everyone would need to bow to their demands.
That's how you make a point. You need to be willing to risk it all in order to make your statement. Sacrifices are expected.