Let's suppose Roosevelt's polio worsens to the point that he dies at some point between the DNC and the 1940 election. In this scenario, Willkie's locked in for the GOP, but who replaces FDR? The Dixiecrats would outright refuse Wallace's nomination in his place, and I imagine a lot of Northern Democrats would be sceptical of his potential elevation beyond the VP slot. How does the 1940 election go without FDR, and who wins? What does this mean for the New Deal and the USA's impending entry into the war? If Willkie wins, does he declare war on Germany immediately, or does he wait like FDR did IOTL? How does US politics change without an explicit two-term limit on the Presidency in place?