Southern Democrats ... I still don’t get it

[Orser67]

This is a really good question, and I encourage you to keep thinking about this regardless of anything you read in this thread.

My personal mental model is that between ~1900 (when Southern Democrats stamped out the Populists) and the 1960s, there were essentially three parties (with the notable exceptions of the ephemeral third-party presidential candidacies of Theodore Roosevelt in 1912 and Robert La Follette in 1924): Northern Republicans, Northern Democrats, and Southern Democrats. Because the South generally didn't have any partisan competition (though there were some early birds), any ambitious/smart/whatever Southern politician would join the Democrats. Pre-1932, Northern Republicans and Northern Democrats were often separated more by ethno-cultural differences than by ideology, but after 1932 Northern Democrats generally moved left of Northern Republicans (with some notable exceptions) and ideology became a more important (although not all-encompassing) factor. So in the North, your average Democrat was to the left of your average Republican, but in the South, pretty much anyone in office, regardless of ideology, was a Democrat.

So with that background paragraph out of the way, what was going on in the 1960s? Southern congressional Democrats tended to win re-election (de facto) uncontested, whereas their Northern compatriots faced actual competition. So Southern Democrats racked up seniority, gaining power within what was then a relatively decentralized Congress. Generally speaking, any major bill would have to go through at least one (if not more) committee in each house of Congress before receiving a vote in each house, and committee chairmen had a huge amount of discretion in bottling up any given bill before even allowing it a vote in their respective committee. One of LBJ's strengths was in courting committee chairmen; e.g. he was able to pass Kennedy's tax cut bill only after convincing Harry Byrd, the conservative Southern chairman of the Senate Finance Committee, that he would seek to balance the budget (it was a different time...).