Arab states don’t even share a working definition of what constitutes terrorism (supposedly the primary target of the joint force): whether the Muslim Brotherhood, for example, is a terrorist group or not.

Arab states will also have to overcome not just political differences but a fundamental lack of trust that has divided them for decades. Even at this early stage, Iraq, a Shiite-majority state with strong ties to Iran, has expressed deep unease about the proposal. One of the most significant and widespread objections is the fear that the force will inevitably be Sunni-dominated, exacerbating sectarian tensions in the region.

There will have to be a significant transformation of relations between Arab governments. Otherwise, as wags have already noted, the joint Arab force could be seen as a “triple oxymoron.” Not “joint,” because of divisions among its members. Not “Arab,” because of sectarian differences, as well as significant numbers of Pakistani, Turkish or other non-Arab troops. And not a “force,” because it either can’t be deployed or proves ineffective.

Even if the plan cannot immediately be implemented, however, the fact that key Arab states are pursuing it demonstrates how gravely they view their strategic situation. After becoming over-reliant on the United States, they fear the Middle East is entering a “post-American” period. So they must move quickly to try to defend their interests.