The U.S. military is now committed to begin a first-of-its-kind joint military operation with Russia, mounting airstrikes against the Islamic State group in Syria.

Yet its not clear what the military advantage will be for the U.S. ground-level operations against the Islamic State.

“With respect to what the Russians might bring to this fight, I’m not going to speculate about that right now,” Lt. Gen. Jeffrey Harrigian, the head of U.S. Air Forces Central Command, told reporters Tuesday. […]