The more I read about it. The more it seems like their used to be 3 parties Dems, Southern Dems and Republicans.
Without disagreeing with what others have written, this is an entirely valid way of looking at the parties from the 1930s to the 1970s (so long as you understand that we're talking about how groups
acted, and not about formal political affiliation). During the 1950s, some academics contended that the United States had a "four party system":
1)the presidential wing of the Democratic Party (controlled by northern liberals)
2)the congressional wing of the Democratic Party (controlled by southern conservatives)
3)the presidential wing of the Republican Party,
4)the congressional wing of the Republican Party
Because the two wings of the Republican Party had fewer differences than the two wings of the Republican Party, I tend to think of it as a three-party system. Northern Democrats, who were generally more liberal than Northern Republicans, generally got to choose the party's presidential nominee. Southern Democrats generally made up a huge portion of the Democratic congressional caucuses, and by virtue of their seniority often chaired the important committees. Congressional Republicans often allied with Southern Democrats (an alliance known as the
conservative coalition) to block liberal legislation (especially during the presidencies of FDR, Truman, and JFK), while Republican presidential candidates were more conservative than their Democratic opponents but less conservative than the occasional Southern third party presidential candidate.
Even prior to the 1930s, the Democratic Party was kind of a weird alliance of Southerners and Northern hyphenated-Americans (e.g. Irish-Americans).
