The USA goes completely dead pretty much after the end of the civil war and this doesn't make me happy. One thing that defenitely needs to be done are good post-war elections.
1944 to 1952 can fire as they normally would.
However, 1940 only fires if both the CSA and AUS no longer exist and that the PSA does not control Denver or Phoenix, in other words the civil war is almost at an end. If the 1940 election does not fire, then there should be an alternative special election in 1942 (1944 will still fire as normal though). Here some vague ideas for candidates:
Garner is in office
1940: Knox/Landon vs. Garner/Wallace
Knox is in office:
1940: Knox/Landon vs. Wallace/Thurmond
1944: Landon/Dewey vs. Wallace/Thurmond
Garner or Wallace is in office:
1944: Wallace/Thurmond vs. Landon/Dewey
Landon is in office:
1948: Landon/Bricker vs. Truman/Stevenson
1952: Eisenhower/Hodges* vs. Stevenson/Sparkman
I know I've missed a few out, but my knowledge of US political history isn't the greatest.
*Considering the damage the nationalist AUS did to the USA during the Civil War, I have my doubts that McCarthyism would pick up and therefore I don't think Nixon would get to become VP.