That is what brought down the unity government of 2007. Abbas would not turn the military (actually a police force. Palestine has no military.) to the legally constituted government. Abbas used these forces, (that are armed, paid, and trained by the US and work for Israel) to overthrow the government in June of 2007.
The Palestinian government has been totally screwed since then.
So if it's not Abbas, then who? I think I have read that Abbas isn't really elected, and if your further claim that he really works for Israel (as others have claimed) then who should the Israelis and the rest of the world be dealing with when they want to deal with the Palestinian leader?
And I did have a thought about Alan Johnston. I wonder if Hamas helped in his return since they want to be the only ones in charge in Gaza.
Abbas was elected, under questionable circumstances, to a four year term on Jan. 9 2005. Not only did his term is office expire in 2009 but in June 2007 he left the government. He quit. He just walked away.
So why didn't hamas convene an EGM and have a new person elected into power, then convene to set up the next round of elections. The could have asked the UN, USA, UK or EU to oversee the elections to make sure they were valid and legal. What do they have to hide that stops them from acting as an elected government ?