“Bukra fil mishmish,” in Arabic vernacular, literally means “Tomorrow, the apricots.” What it really means is “it will never happen.” The window for harvesting apricots is so tight that if one puts it off for even a day, they go rotten.

It’s now political apricot season in the West Bank and Gaza. Against all odds, the rival Hamas and Fatah factions made a surprise announcement in April that after four years of internecine fighting, they would join a Palestinian unity government. Now, only six weeks later, Hamas has refused to accept Salam Fayyad, Fatah’s choice for prime minister.

Fayyad is an accomplished technocrat, and without him, Palestinian state building stops. This explains why Haaretz and other Israeli outlets are reporting that Palestinian President Mahmoud Abbas now favors returning to negotiations with Israel rather than pursuing a vote on Palestinian statehood at the United Nations General Assembly in September. In recent months, Fatah leaders had galvanized international support for this unofficial recognition of the West Bank (now under Fatah control) and Gaza (now under Hamas control) as one Palestinian state. The failure to unite these two territories will only serve to buoy Israeli claims that the Palestinians are not ready for statehood. It will also force European states that had planned to vote in favor of the UN resolution to confront the reality that the Palestinians may once again have no sovereign government under which to unite. Rather than pursue their international aims, the Palestinians will be forced to face their decidedly inconvenient internecine conflict. This may might push them into renewed conflict.

This short-lived unity really should come as no surprise. The ideological differences between the Islamist Hamas organization and the nominally secular Fatah cannot be overstated. Members of Fatah will not easily forget the coup of 2007 in which Hamas, with Iranian backing, killed hundreds of their members.

This deep-rooted animosity was glaringly apparent last month when the two sides settled on the vague language of an agreement in Cairo. Palestinians in the West Bank and Gaza flashed their signature “V” for victory signs to photojournalists, and the New York Times called the moment “historic,” but in a sign of lingering acrimony, neither Hamas leader Khaled Meshal nor Abbas signed the agreement themselves.

The two factions seem unable to help themselves. Recently, Hamas hammered Abbas for agreeing to join peace talks with Israel sponsored by the French government. Last month, Hamas lashed out at Fatah for its apparent lack of willingness to release Hamas prisoners, claiming that it amounted to “sticks in the wheels of national reconciliation.” Thus even as Palestinian media outlets crowed about international support for the new unity arrangement, a Hamas official warned that “reconciliation will not be materialized as long as the members of the (Hamas) movement in the West Bank are not freed from the PA prisons.”

Now that Hamas has rejected Fayyad’s candidacy for prime minister, latent hostility has once again bubbled over the surface, raising troubling questions about Palestinian national identity. As the September vote draws nearer, this will become nearly impossible for the international community to ignore.

While the two sides may still have time to salvage their agreement, the window in which they can harvest the fruits of reconciliation appears to be closing fast.