On Wednesday, rival Palestinian factions Fatah and Hamas officially ended a four-year rift by signing a landmark reconciliation agreement. Palestinian President Mahmoud Abbas said the accord ends "four black years" that hurt Palestinian interests, and promised to visit the Hamas-held Gaza Strip soon. Under the deal, the rival groups — Fatah, backed by the West, and Hamas, widely dismissed as a terrorist organization — will form a joint government to rule until elections can be held next year. Israel, which has denounced any government that includes Hamas, has at least been able to talk to Fatah in the past. Are those days gone?

This accord is a "disaster": The gaping differences between Fatah and Hamas cannot be reconciled, says Michael Weiss at The Telegraph. Fatah leaders, for instance, called Osama bin Laden's death the end of a "very dark era," while Hamas condemned the U.S. for killing "an Arab holy warrior." Abbas wants to unite his people, but "how can the noble cause of Palestinian nationalism be squared with supporting an anti-Semitic terrorist organization which views al Qaeda as People Like Us?" This untenable pact is a "disaster."
"The Fatah-Hamas agreement is a disaster waiting to happen"

It may be a necessary step toward peace: "This is a decisive moment," says former President Jimmy Carter in The Washington Post. If the U.S. and other nations get behind the interim government, they will be helping Abbas' effort to "make a secure peace with Israel" on behalf of all Palestinians. But if the world undermines the reconciliation effort, "the situation in the occupied Palestinian territory may deteriorate with a new round of violence against Israel."
"Support the Palestinian unity government"

The deal could still fall apart on its own: Don't overlook the "violence both organizations have used against each other, especially Hamas toward Fatah," say Avi Issacharoff and Amos Harel in Israel's Haaretz. They will fight over who leads the interim government, and the whole thing could fall apart if, as expected, Hamas refuses to recognize Israel for the first time.
"Hamas and Fatah may have reunited, but their work is just beginning"