“For weeks, Mr. Hussain was careful to keep his young stepson by his side, and the drones held their fire. But late one night, Mr. Hussain left an internet cafe alone, and minutes later a Hellfire missile killed him.” What role did Junaid Hussain play in ISIS and why was the US so intent on killing him? The answer to that question explains much about one of the key fronts in the battle against terrorism (and in just about every other modern battleground, both military and political). One by one, the FBI is killing social media experts. (This could be the only known way to cure a social media addiction.)