Here is the difference from WW2/Depression. Back then the USA had a sober, intelligent leader with foresight (he armed the British even when the US was neutral, through the Lend Lease program). Despite his paralysis, he flew half way across the world to seal an alliance with the Soviets. And lest one thinks he was taken for a ride, here is the comment Stalin made about him - Churchill will pick your pocket for little things. Roosevelt steals the bigger things.

Back then Germany had an erratic leader who had an astonishing run of political and military successes. 

Today the US president is erratic, and has had astonishing political success.

Chinese curse - May you live in interesting times.