JERUSALEM — As the rival Palestinian factions Fatah and Hamas began unity talks on Tuesday in Cairo, one detail stood out as emblematic of the challenges they face: The delegation representing Hamas is led by a man who has been accused of plotting to overthrow the president of the Fatah-dominated Palestinian Authority, Mahmoud Abbas.



If that awkward hurdle can be overcome, the talks would have at least the potential to end the decade-long, sometimes bloody schism between the two groups and reshape the region’s political map. The effort is being propelled to a great extent by the increasingly desperate humanitarian situation among the two million residents of Gaza.

That being said, few here think the two groups will bridge their differences.

From the outset, they are approaching the Egyptian-sponsored reconciliation process with divergent, and often mutually exclusive, ideas of where the talks should lead and even of what unity means.

The aging and unpopular Mr. Abbas, whose Palestinian Authority holds sway in part of the Israeli-occupied West Bank, hopes to wrest back control of the Gaza Strip from Hamas after a 10-year absence. Hamas says it has disbanded its administrative control of Gaza and relinquished all responsibility for civilian affairs there. But it sees unity as an opportunity to regain a foothold — and eventually take over — in the West Bank.