There are not that many diplomats in Russia. Based on reports by the State Department's Office of the Inspector General, the majority of U.S. Mission Russia employees are not Americans, and won't be expelled: Of 1,200 people employed in 2013 in Mission Russia, 333 were U.S. citizens and 867 were Foreign National Staff, most of whom were probably Russian nationals. Using the 2013 numbers, if the U.S. Mission is forced to let go of 755 people, a majority of them would not be U.S. citizens, and probably would not be expelled from the country. American employees of U.S. Mission Russia don't all work for the State Department. They also work for the Defense Department, the FBI, the Agriculture Department, NASA, DEA, Commerce Dept, Defense Threat Reduction Agency, etc.