For the second time since the U.S.-led effort to counter ISIS began, the chairman of the Joint Chiefs of Staff, Gen. Martin Dempsey, said he would not rule out asking the President to send U.S. ground troops into Iraq. 

"I've never been limited in my ability to make a recommendation of any size or sort to the President of the United States," Dempsey told the House Armed Services Committee on Thursday, adding that he is always re-evaluating the situation in Iraq. 

Dempsey told the committee that he could envision scenarios in which a U.S. ground contingent would be necessary in Iraq, particularly if the coalition moves to retake Mosul or the western border with Syria. 

"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," cautioned Dempsey, "but we're certainly considering it." 

Rep. Buck McKeon, R-California, the committee's chairman, expressed concern about President Obama's consistent refusal to consider sending U.S. ground troops to the region. 

"I will not support sending our military into harm's way with their arms tied behind their backs," McKeon said, adding he would block any congressional authorization that specifically barred sending ground forces. 

And while Dempsey said he would not rule out the need for U.S. ground troops in the future, he added: "I just don't foresee a circumstance when it would be in our interest to take this fight on ourselves with a large military contingent." 

Throughout the hearing, Dempsey and Defense Secretary Chuck Hagel described a mission in Iraq and Syria that will likely be long and fraught with setbacks. 
who is he?
 the committee's chairman,