President Obama’s top military adviser said Thursday that he would consider deploying a limited number of United States forces to fight alongside Iraqi troops moving to retake Mosul and other areas under the control of Sunni militants, opening the door to a riskier, more expansive American combat role in Iraq than President Obama has publicly outlined.

Gen. Martin E. Dempsey, the chairman of the Joint Chiefs of Staff, told the House Armed Services Committee that Iraqi troops — who initially fled under the onslaught of Islamic State militants — were now doing a better job of standing and fighting. But he said he could not rule out the possibility that as operations against the Sunni militants move into more complex phases of clearing Islamic State militants out of cities and other territory they hold, American troops may have to help their Iraqi counterparts.

“I’m not predicting at this point that I would recommend that those forces in Mosul and along the border would need to be accompanied by U.S. forces, but we’re certainly considering it,” General Dempsey said. […]