This latest ideological change is most conspicuous in descriptions of who the United States is at war with. The enemy has always been overly classified and somewhat hidden, but at least there was once a recognized list of discrete groups. Now, the adversary is an undefined and contested category of groups or people allegedly connected with the act of terrorism. If the U.S. government were as imprecise with its bombs as with its descriptions of its terrorist enemies, it would be a war crime. This matters: If you cannot name your opponents, you certainly cannot know them, much less measure progress in defeating them.

Consider the nebulous jumble of abstract enemies that officials have pronounced. In February, President Barack Obama said, “We are at war with people who have perverted Islam” and said that the international community must “eradicate this scourge of violent extremism.” Similarly, when attempting to describe the enemy, the chairman of the Joint Chiefs of Staff, Gen. Martin Dempsey, claimed that the United States is in a fight “against the group that has perverted Islam.” In February, National Security Advisor Susan Rice contextualized the U.S. mission as “to cut off violent extremism at the knees.” Earlier that month, she attempted to describe the undefined enemy: “As al Qaeda core has been decimated, we have seen the diffusion of the threat to al Qaeda affiliates, ISIL, local militia[s], and homegrown violent extremists.” Eric Holder, then the attorney general, claimed, also in February, that the United States is simply “combating the threat of violent extremism.” Gen. Lloyd Austin, commander of U.S. Central Command, said the enemy is “ISIL and other violent extremist groups.”

Some policymakers have been even vaguer. When asked to define the enemy, Secretary of State John Kerry said, “I call them the enemy of Islam.” Let’s set aside the fact that Kerry is now presuming to interpret what is legitimate faith for 1 billion Muslims. Just who is this enemy precisely?