One of the core ideas behind the United States Constitution is federalism—the division of power between the central government in Washington and the multitude of state and local governments. The Constitution explicitly assigns responsibility for national defense and foreign policy to the U.S. government. This has been the case for over 200 years. However, the Cambridge City Council seems to be oblivious to this time-tested arrangement. Instead, it routinely attempts to extend its reach into matters of national and foreign policy. Take for example its Policy Order Resolution of July 30, 2007, which called for “withdrawal of U.S. troops from...