Immediately following the Japanese attack on Pearl Harbor, U.S. Secretary of the Navy Frank Knox issued a statement that "the most effective Fifth Column work of the entire war was done in Hawaii with the exception of Norway." In a column published in "The Washington Post", dated 12 February 1942, the columnist Walter Lippmann wrote of imminent danger from actions that might be taken by Japanese Americans. Titled "The Fifth Column on the Coast", he wrote of possible attacks that could be made along the West Coast of the United States that would amplify damage inflicted by a potential attack by Japanese naval and air forces. Suspicion about an active fifth column on the coast led eventually to the internment of Japanese Americans.