The course of relations between Germany and the United States had deteriorated since the beginning of World War II, inevitably so given the increasing cooperation between the United States and the United Kingdom. The Destroyers for Bases Agreement, Lend-Lease, the Atlantic Charter, the hand-over of military control of Iceland from the United Kingdom to the United States, the extension of the Pan-American Security Zone, and many other results of the special relationship which had developed between the two countries had put a strain on relations between the US, still technically a neutral country, and Nazi Germany. US destroyers escorting American supply vessels bound for the UK were already engaged in a de facto war with German U-Boats.[2] Roosevelt's desire to help the UK, despite the objections of the influential US isolationist lobby, and legal impediments imposed by Congress which prevented direct involvement in the war, brought the US to push hard against the traditional boundaries of neutrality.