Here's my guess as to when it happened, Bobert. I think it happened when the Republican Party decided that it could permanently secure a certain bloc of votes (disaffected and angry mostly rural working class Whites deeply afraid of social change) by using the politics of division and fear to manipulate them.

And when did that happen? Very shortly after Barry Goldwater's huge defeat in the 1964 election. That was when the Republican Party got hijacked by a bunch of neocon idealogues who decided to appeal to the most reactionary and fear-driven elements in American society, paint the Democrats as an un-American, northern, intellectual elite of composed of pansies who are soft on Communism and probably are socialists (gasp!) to boot, and thereby gained themselves the presidency by playing on those themes in a completely unscrupulous and divisive manner.

And it worked! (most of the time) The Democrats did not understand how the heck to deal with political opponents who played the role of "Super Patriot", because if you oppose that role, they call you "unpatriotic" and "elite", and that's the kiss of death in the USA.