An emissary to judge whether the island will hold

At the beginning of 1941, President Franklin D. Roosevelt wants to help a besieged Great Britain, but runs up against an American public opinion still largely isolationist. He is preparing the Lend-Lease law, which is to make it possible to supply arms and provisions to London without immediate payment — an enormous and contested commitment in Congress.

Yet a nagging question undermines the decision: can Great Britain really survive? Investing billions in a nation that would collapse a few months later would be a political and strategic disaster. Roosevelt is wary of the official reports, sometimes too optimistic or too pessimistic depending on their source, and of his own outgoing ambassador, the defeatist Joseph Kennedy.

He has at his disposal a man of confidence out of the ordinary: Harry Hopkins, an intimate adviser, sick and without official portfolio, but endowed with all his personal credit. Roosevelt considers sending him to London as a private emissary, to gauge from the inside the will to resist of Churchill and the British people. But the option carries risks: an unofficial mission might appear a disavowal of regular diplomacy, and the opinion of a single man, however close, would weigh heavily in a momentous decision.