How did he work with Roosevelt and Churchill to achieve these goals?

He worked closely with President Roosevelt and Prime Minister Churchill through frequent meetings and strategic discussions, fostering a collaborative approach to address their shared goals during World War II. This included coordinating military strategies, sharing intelligence, and establishing key alliances, such as the Atlantic Charter, which outlined their vision for post-war peace and cooperation. His diplomatic efforts were crucial in aligning their visions and ensuring a united front against the Axis powers.