Successive US presidents, from George Washington to Franklin Roosevelt, did not prioritise establishing a peacetime foreign intelligence capability. For most, there was no need. The Republic was flanked by two vast oceans and had weak or friendly neighbours. It was prosperous and secure. Some presidents were naive about intelligence. President Woodrow Wilson attested to his own ignorance of the subject in 1919: ‘Let me testify to this, my fellow citizens, I not only did not know it until we got into this war, but I did not believe it when I was told that it was true, that Germany was not the only country that maintained a secret service. Every country in Europe maintained it.’ And many senior American politicians considered the business of espionage ungentlemanly and un-American. Secretary of State Henry Stimson noted in his autobiography that he closed America's ‘Black Chamber’ because ‘gentlemen don't read each other's mail’.Consequently, the US was the last of the great powers to establish a coordinated intelligence machinery.

Certainly, wars, foreign and civil, had prompted the creation of detective agencies, secret services and rudimentary intelligence organisations. The US was no stranger to intelligence per se. But the effort was haphazard and episodic. George Washington depended on espionage during the Revolutionary War; both Union and Confederate forces established sundry spying organisations during the Civil War. The Office of Naval Intelligence (ONI) was formed in 1882, and a Military Intelligence Division (MID) followed in 1885. Both were small, poorly resourced and under-utilised.Both grew significantly with US involvement in the First World War.Both were severely cut following the armistice.The first US codebreaking office, MI-8, was founded in June 1917 under Herbert O. Yardley, and achieved the significant distinction of surviving into peacetime. MI-8 became the Cipher Bureau, and went on to attack Japanese, German and British Ciphersbefore having the rug pulled from beneath its feet by Secretary of State Stimson in 1929.A rump sigint capability was preserved in the Army and Navy, which achieved some notable successes against Japanese cipher systems. But throughout the 1930s, the overall US intelligence effort was fragmented, often amateurish, and lacked a customer base in the armed forces or government who accorded it the priority it deserved, even as the threat of world war grew.