Like 1812 when the Brits weren't busy with the French they easily came in and burnt the US capital as punishment for burning the Canadian one. It's not that the British army suddenly got a lot stronger; they just weren't busy fighting on two continents.
That said, civil disobedience is largely pointless. We're in a capitalistic society so money is the name of the game. Rosa Parks did shit-all; it was the boycott of the bus system for 9 months that made the buses cave.