The top US military official said Monday he is “a bit concerned” about whether the international coalition fighting the Islamic State is sustainable for the longer-term challenge of confronting extremists in other regions.

Army Gen. Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff, told reporters traveling with him that the basis of his concern is the possibility of continued sectarian divisions in Iraq.

Dempsey said that in military terms the campaign against IS is “on path.” But he put equal emphasis on the importance of sustaining the coalition for the longer term. Shiite dominance in Baghdad upsets predominantly Sunni countries like Saudi Arabia and the United Arab Emirates. […]