Goldwater lost but it surprised most strategists that he was able to carry the deep south, historically a democratic stronghold since the end of the civil war,

Goldwater lost but it surprised most strategists that he was able to carry the deep south, historically a democratic stronghold since the end of the civil war, particularly with blue collar workers. This was essentially due to Goldwater's opposition to the Civil Rights movement. This observation became strategy, to use the movement as a wedge issue to convince conservative southern democrats to switch allegiance. Before this, the distribution of conservative to progressive, while still slanted, was more even than afterwards. The trend continued through Nixon, Reagan, Newt Gingrich, GWB, and now Trump. It's largely been the same cohort of voters driving this trend, and their views have been becoming more radical vs centrist. Among democrats you can see some attempts to cater to these voters as well like with Bill Clinton. Another big part of it is the rise of the evangelical right to top level influence in the republican party as well. There's certainly a whole heck of a lot more to the story than this, but when you go digging through the dispassionate history and summaries, this realignment is clear. In some sense the republican leadership is now being hoisted by their own petard, as the more classical or centrist ones show in relation to how they respond to Trump's most extreme actions. We're probably headed for another realignment, but I think anyone claiming to know what will trigger it or how it will shake it is far too confident of their own clairvoyance.