That seems rather arbitrary, the Confederate states were won by your "Northern" winner in 1868, 1872, 1956, 1968 (a plurality of EVs), 1972, 1980, as well as 1928 if you consider Oklahoma to be a Confederate state (Indian and Oklahoma territories fought with the Confederacy). Your "Southern" winners would still have won without the Confederate states in 1892, 1912, 1932, 1936, 1940, 1944, 1948, 1960, 1964, 1984, and 1988. And how is Reagan "Northern" in 1980 and "Southern" in 1984, while Nixon isn't in '68/'72?
