Mohammad Dahlan, a former Palestinian Fatah leader in the Gaza Strip who became a nemesis to Palestinian Authority President Mahmoud Abbas and who now lives in exile, has collaborated with Hamas, setting up the possibility of a move against Abbas that could conceivably result in some form of unity between factions. Dahlan was at one time considered a favorite of Western nations to assume leadership of the Palestinian Authority. A senior Hamas official said on Sunday that they are working with Dahlan “on social interests after Abbas crippled those interests.”