What qualities make a strong leader?
If a leader did not have the qualities needed to be a leader then they should have never been assigned the role of the leader. Some people are not assigned leader but just looked at as the leader and when someone is looked up to people typically follow what that person does; so if they do not have the right qualities then most likely the team will not be all that great.
What qualities made Washington a good leader is when times got tough he got tougher. Even when his troops got tired and ran out of will power he got them back on their feet and reminded them what they were fighting for. That's what made Washington a great leader. His ability to make decisions in such a short amount of time made him a respected man, and leader.
You don't say which leader you have in mind, but generally speaking, history has shown that for any Middle Eastern leader to survive, he must be a forceful personality. This was true then as it is now. Other key qualities were then: he had to be a good and succesful army leader, lawmaker and administrator.