Will 'racist' replace 'liberal' as the new national slander word? ?

In a way, yes. For the past eight years the opposition to the President was invariably labeled "liberal". Now the opposition to the President will be labeled "racist". From that perspective you are right on target. I do, however, mourn the loss of free discourse. The term liberal, no matter how meanly meant could never be considered, in and of itself, derogatory. Liberal is a way of thinking which one may or may not agree with and there have been many laudable liberals. I cannot remember any racist who deserves such praise. Racist is clearly a derogatory term and I am not aware of anyone who will want to be considered racist. What a great way to drown out dissent. Any person suggesting that the President has made a mistake will immediately be termed a racist and that will be that.