Doug:  first, I'd be happy to play "grammar pedant" with you anytime....just let me know. 

The southern strategy was implemented over several decades.. In fact, it's still being implemented.  To be sure the Civil Rights and Voting Rights Acts "started the ball rolling" for the migration of racists from the Democratic Party to the GOP.  Only a hard-core Trump fan would deny the "dog whistle" component of Trump's campaign and Presidency regarding racism.  Gary Crum