By October 18, the president and his advisers weighed only two options: blockade or invasion.
White House
1962-10-18
The John F. Kennedy Presidential Library and Museum, Boston. <a rel="nofollow" class="external autonumber" href="http://www.jfklibrary.org/jfkl/cmc/cmc_tcsmemo_oct18.jpg">[1]</a>