By Jeremy Bowen
BBC Middle East Editor
It was a momentous day for Palestinians.
The recent fighting has left Hamas militants in control of much of Gaza
By the evening, Palestinian Authority President Mahmoud Abbas had taken the decision to dismiss the elected Hamas prime minister and to declare a state of emergency.
It was drastic action, but it cannot do much to touch the Hamas military wing in Gaza.
It is not clear how much influence even the elected Hamas politicians there have over events.
The fighting has left masked Hamas gunmen in control of most of the centres of
power in Gaza.
Fatah's vaunted Preventive Security Force has been defeated, and its headquarters seized.
The Hamas fighters in Gaza won because they were better trained and better led than those of Fatah.
Many of the forces that Fatah might have expected to have on its side did not take part in the fight, some melted away.
Other local Fatah leaders worked out non-aggression pacts with Hamas.
Mohammed Dahlan is a key ally of the US, seen as a traitor by Hamas
The men who did fight were loyal, in the main, to Fatah's strongman in Gaza, Muhammad Dahlan - the man the US hoped would bring down Hamas.
But he was not there to lead them, and neither were other key Fatah figures.
Mr Dahlan is the prime enemy of Hamas. He is a key ally of the US, and also regarded by Israel as a necessary man.
The US has been working hard to help Mr Dahlan strengthen his forces.
He was absent, having medical treatment in Egypt, when a Hamas gunman kicked open the door of his office and put a bullet into his desk.
He has now returned to Ramallah, in the West Bank, where he is with Mr Abbas.
State of emergency
The man who shot up Mr Dahlan's office was filmed shouting: "This is the fate of traitors like the scumbag Muhammad Dahlan!"
A state of emergency is supposed to bring violence under control. The risk is that this one will make it worse.
Some Palestinians fear that the end of the unity government could cause the collapse of the Palestinian Authority and the other institutions they had hoped would become part of the apparatus of an independent state.
The institutions, and the hopes behind them, have already taken a severe battering from Israel's military actions over the last seven years and, more recently, by the punishing financial sanctions imposed by Israel and other countries after Hamas won a free election at the beginning of last year.
The events of this week feel like a breaking point.
One Palestinian analyst contacted by the BBC said he feared the damage being done to Palestinian society by the current meltdown and the years of pressure that created it would be on a par with the destruction of Palestinian social structures in 1948, when Israel was created.
It is an event Arabs still refer to as "the catastrophe".
What has happened also shows the failure of the decision of the world's big powers to isolate Hamas.
Prime Minister Ismail Haniya is under pressure to negotiate
The financial sanctions they imposed, which caused severe hardship and helped fuel the violence in Gaza by making people even more desperate, were designed to either force Hamas to recognise Israel or to push it out of power.
The policy has achieved neither objective.
The Saudis, who have given Mr Abbas vital backing, will not want to see the end of the unity government, since they worked hard to create it.
It was supposed to be the centrepiece of a new activist Saudi foreign policy.
The Hamas Prime Minister, Ismail Haniya, will want to maintain a working relationship with Mr Abbas. Without it, Hamas will be even more isolated.
So Saudi Arabia, and Egypt, will try to force Hamas and Fatah to negotiate.
If they cannot, and their future is to spill each other's blood over rival statelets - Gaza and the West Bank - under the eye of the occupying power, Israel, then they have no chance of a wider Middle East peace deal.
The military leaders of Hamas do not believe one is possible anyway.
And that would mean that the dream so many Palestinians have of an independent state will die for another generation.