If there were any doubts the 1960s are over, they were put to rest Tuesday night when our new first family won the hearts of the world as it emerged on that vast blue stage to join the celebration in Chicago’s Grant Park. The bloody skirmishes that took place on that same spot during the Democratic convention 40 years ago — young vs. old, students vs. cops, white vs. black — seemed as remote as the moon. This is another America — hardly a perfect or prejudice-free America, but a union that can change and does, aspiring to perfection even if it can never achieve it.