We recently received—via a third party—a critique of our report, Countermeasures. The critique, written by Uzi Rubin and titled “Comments on the UCS Report on Countermeasures,” is dated 18 July 2000. Rubin states that his study was “considerably less exhaustive” than the countermeasures report and was done by “a small team of experienced missile engineers.” Rubin’s critique has not been published, but instead has been distributed informally in the United States. Here we respond to Rubin’s points in the order that he makes them. As we will make clear, Rubin’s criticisms are either technically invalid or based on incorrect characterizations of the assumptions that underlay our work.