Five weeks after Islamist fighters stormed across northern and western Iraq in a surprise offensive that nearly reached the outskirts of the Iraqi capital, virtually every captured location remains firmly in rebel hands, while the central government’s meager efforts at a counteroffensive have met with failure on virtually every front.

Worse yet, Iraqi and U.S. officials have confirmed that fighters allied with the Islamic State not only captured hundreds of U.S.-supplied Humvees and large amounts of ammunition in their march across Iraq, but they also now possess as many as 52 U.S.-supplied artillery pieces with GPS aiming systems. The 155mm guns have a range of 20 miles, putting many Iraqi cities still in government hands easily within range of Islamic State positions.

Even the Iraqi government’s military briefings, consistently upbeat, hint at the grim outlook: The list of accomplishments cited by the Iraqi military’s spokesman are almost entirely defensive, making it clear that the Islamic State remains on the offensive and in control of when and where fighting takes place. […]