[223] As that conflict drew to a close in early 1939, Roosevelt expressed regret in not aiding the Spanish Republicans.[224] When Japan invaded China in 1937, isolationism limited Roosevelt's ability to aid China,[225] despite atrocities like the Nanking Massacre and the USS Panay incident.[226]

The Roosevelts with King George VI and Queen Elizabeth, sailing from Washington, D.C., to Mount Vernon, Virginia, on the USS Potomac during the first U.S. visit of a reigning British monarch (June 9, 1939)
Foreign trips of Roosevelt during his presidency[227]
Germany annexed Austria in 1938, and soon turned its attention to its eastern neighbors.[228] Roosevelt made it clear that, in the event of German aggression against Czechoslovakia, the U.S. would remain neutral.[229] After completion of the Munich Agreement and the execution of Kristallnacht, American public opinion turned against Germany, and Roosevelt began preparing for a possible war with Germany.[230] Relying on an interventionist political coalition of Southern Democrats and business-oriented Republicans, Roosevelt oversaw the expansion of U.S. airpower and war production capacity.