In recent years, the process of providing legal advice at the highest levels of government has sparked significant controversies. The present article uses advice given to President Franklin Roosevelt by Attorney General Robert Jackson, later Justice Jackson, to explore this advisory process. There is no comparable, in-depth study of the relationship between any president and the president's legal advisors. The United States was a neutral country in the summer of 1940, and Great Britain stood alone against a triumphant Nazi Germany. President Roosevelt transferred fifty American destroyers to the British in their hour of need, and the president relied in part upon Jackson's formal written advice that the transfer would be lawful. This episode, which involved a respected president and a respected attorney general, provides an invaluable laboratory for exploring the advisory process. Discussions of legal advice given to presidents over the last decade are inevitably distorted by rancorous partisanship. In contrast, Attorney General Jackson's advice is distant in time and relatively uncontroversial. Today, everyone agrees that the substantive policy of supporting Great Britain against Nazi Germany was the right policy. Based upon an in-depth study of Jackson's conduct, the present article concludes that the traditional principles of professional responsibility provide an inadequate basis for understanding the relationship between a president and his legal advisers.