But as Obama prepares for his second term in office, one of his top defense officials is arguing that there is an end in sight, and laying out conditions for when the U.S. will reach it.

“On the present course, there will come a tipping point,” Jeh Johnson, the Pentagon’s top lawyer, told the Oxford Union in the U.K. on Friday, “a tipping point at which so many of the leaders and operatives of al-Qaida and its affiliates have been killed or captured, and the group is no longer able to attempt or launch a strategic attack against the United States, such that al-Qaida as we know it, the organization that our Congress authorized the military to pursue in 2001, has been effectively destroyed.” At that point, “our efforts should no longer be considered an armed conflict.”