When Hamas won the January 2006 election in Palestine, but were not allowed to take power, they eventually formed a power sharing government with Abbas' Fatah and some deals for practical implementation of the unitary government were put in place. One of these deals was that 'security' in Gaza would be put under the control of the Government in a unified force, rather than the collection of private militias that had existed since Arafat's time. These militia, you may recall, were responsible for kidnappings, including the BBC journalist Alan Johnson. A quick search of the BBC for "Johnson Gaza" brings up Jul 2004 - 'This weekend a string of high profile kidnappings and fighting...' April 2003 - 'Dahlan says he will disarm other militias by force if necessary', and so on. Johnson was captured on March 12th 2007 by the Dogmush clan, another fearsome tribe that had been allowed to run wild whilst Dahlan was head of security in Gaza under Arafat and then Abbas.
The reason for the kidnap at a time when Hamas looked certain to beat Dahlan, seems to have been an excuse to bring in International - ie Israeli - forces against Hamas, who had been fighting Dahlan as part of their mission to unify security, agreed as part of the coalition settlement. Dahlan was supposed to slot into the Hamas Parliamentary chain of command, but that was never going to happen after Israel - who preferred Gaza split, unstable, corrupt and divided - gave him a boatload of arms, and in the end the fighting became very bloody, but Hamas 'won'. Dahlan fled to the West Bank, where he was found a job in Tony Blair's re-organisations, but that spelt the end of any Hamas input there, as a wave of arrests of Hamas activists by Abbas, and Hamas MPs by Israel, took place.
So, the removal of Dangerous Dahlan is bravery by Abbas beyond what I would have considered possible. Does that make Abbas weak or strong? The BBC quotes him as under pressure, which he is, but I see this as poke in the eye for Israel, and a statement of independence from Abu Mazan (Abbas).
In Israeli eyes Abbas has been behaving strangely lately: he's refused to obey Israel slavishly, he insists on the settlement ban, and by removing Dahlan, he may actually be clearing the way for a dialogue with Hamas. So, as with Arafat, Israel'd want to get rid of him, so the coup charge against Dahlan looks realistic. And therefore getting rid of Dahlan is very brave, and a smack in the teeth for Netanyahu, isn't it? Well, I've always been a glass half full man, because otherwise I'd have to cut my wrists, it's so depressing, so let's look at the picture in the round.
Abbas had not folded in his demand for a settlement moratorium, he has a plan B (declare an independent state of Palestine) to go forward diplomatically in the face of Israeli Intransigence which is meeting with some success, and he has just got rid of the one man that Hamas would want him to, opening the way for genuine dialogue. He is now in a position where he can be a little bit generous to Hamas - even if Israel will portray that as weakness. A united front will be important to get a first ever Security Council Resolution against Israel's brutality, and then the Gaza Boats will be on the seas again in May, again with a powerful Turkish presence making it hard for Israel to sustain the Gaza blockade AND any credibility as a peace-loving state. Obama doesn't have to do anything, he just has to sit on his hands, and let it all happen. I think Abbas thinks he can actually achieve something, and I hope he's right.
Here's the BBC article in full; what a shame that it doesn't seem to feel it necessary to tell us Dahlan's blood-stained history:

- Palestinians pursue 'Plan B' after failed talks
- Profile: Fatah Palestinian movement
- Young leaders dominate Fatah vote

