In the wake of the Islamic State's (IS) attacks in the Sinai Peninsula, Beirut and Paris, there is an urgent need to mobilize resources to deal with the threat, especially resources in the Arab world. Instead, Saudi Arabia and its Gulf allies are devoting their resources and efforts to a floundering and expensive military campaign in Yemen.

When the air campaign against IS began more than a year ago, the Royal Saudi Air Force was an early participant. But it has not flown a mission against IS targets since September, according to The New York Times. Bahrain last flew a mission against IS in February. The United Arab Emirates stopped in March — even Jordan stopped in August.

There has been no formal or public announcement of the stand-down. The Arab governments all reiterate their strong opposition to IS. This week, Riyadh's skyscrapers were lit in the French colors to express solidarity with Paris. King Salman bin Abdul-Aziz Al Saud told President Barack Obama in Ankara that Saudi Arabia will play a major role in Syria. But in practice, American military officials report the war in Yemen has drained Arab air power away from the fight with the terrorists in Syria and Iraq. Yemen is the priority even if some token operations occasionally are taken to strike IS targets.

The absence of Arab air forces creates a political — not military — void, even though Russia, France and America are fully capable of waging an air war against IS. The coalition is missing the Muslim answer to the self-proclaimed "Caliph Ibrahim." This is a waste of symbolically important resources.