Shortly before Obama's first election to the office of president, blatantly racist talk, even the appearance of it, was in the category of proscribed speech in the public sphere---Even certain kinds of dog-whistles were enough to ruin the career of public figures.  

After he got elected, this changed; racist references to an Obama presidency, including birtherism, garnered big constituencies as the Big Tent got opened to fringe elements of the far right, and their views became more legitimized in public discourse.  That and the ACA, a republican proposal requiring all Americans to have health insurance (something I don't think is going to change under Trump), are really the only significant "changes" brought by an Obama presidency. 

The right's new "populism" delivered both houses of congress, and now the presidency, to the repubs, powered in part by a tacit national podium for white nationalism---Is this almost-forgotten bad dream the one you meant?