The Trigger That Triggers Revolution

The trigger that triggers revolution is almost always the regime doing something. That's why the protests surrounding International Women's Day were able to roll so seamlessly into demonstrations from the Petrograd garrison. If a breakaway group from inside the ruling class takes power without introducing any popular forces, it's probably just a coup d'état. Only when the ruling class is divided and when a major faction is ready willing and able to ride popular waves rising up in the street do we get a revolution?