Recently released documents suggest that the US felt the annihilation of Soviet and Chinese urban areas to be a plausible option in the event of a nuclear war. According to the Single Integrated Operational Plans (SIOP) of 1962-1964, documents used as a guideline for nuclear weapons in the case of a war, Washington was considering hindering the industrial capability and destruction of "viable" society in its two rivals as one objective in a retaliatory strike scenario.
Among the first priority targets in these plans were ICBM cites, airfields and other military objects. However, the last level of priority, so-called "Charlie targets" included urban areas. The objective was to destroy a country's ability to wage war and to remove China and USSR from the category of major industrial powers; to ensure a favorable place for the US in the post-war world.
Moreover, the authors of the plan realized that such strikes would cause severe casualties among civilian populations and even considered them as "the primary yardstick for effectiveness in destroying the enemy's society." They, furthermore, put more emphasis on population losses rather than on the destruction of industrial equipment because it would be useless without workers to operate it.
At the same time, the set goal of exterminating 30% of the population in the nuclear strikes was deemed hardly achievable for China, because the SIOP review pointed out that 84% of China's population at that time lived in rural areas.
In December 2015, the National Archives and Records Administration published a list of key objectives for nuclear bombing by the US in accordance with 1959 plans. According to these plans, the US targeted the USSR, China and Eastern Europe with at least 179 objects in Moscow, 145 in Leningrad (now known as St. Petersburg) and 91 in East Berlin.