A constitution is nice (the US one is very nice even), but when the velvet glove comes off, it's just a piece of paper. As Stalin is claimed to have quipped when criticised by the Vatican: "The Pope? How many armoured divisions does he have?" At the end of the day, there's power and power rests always on the will and abilty to do violence to others until they comply. A constitution isn't much use except as a rallying point, but without the will to power it is nothing.