Universities now teach that the parties swapped at some point.
I guess is was at some point AFTER LBJ.
Nixon appealed to law-and-order Southern Democrats in the ‘68 election and that put him over the top against Humphrey. Reagan appealed to blue-collar Dems in 1980. Trump picked up just enough of both in 2016.
But ‘68 was the year of “inversion” and the solidly Democratic South began to become more reliably Republican.
True, many of the Democrat Dixiecrats switched to the Republican Party after LBJ’s Civil Rights Act was implemented. It was also promoted by part of a Republican “Southern Strategy.” I was alive and interested when all that was going on. Universities are NOT inventing this.