I believe the best days are ahead. We defeated the racist slave holders in the south and have kind of kept them in check. Defeated Hitler and the old Soviet Union.
Right now, the country is in an undeclared war with conservative confederates and right wingers who are trying to destroy the nation because they think we can "start over". They mistakenly believe this was "their" country and they scream they want it back. Fortunately, they are old and won't last much longer thank God.
The truth is this is a nation of immigrants. You can come here and become an American. You can go to Japan, but will never become "Japanese". It's the diversity that makes the US great. The mixing of ideas. The right wing has walled itself off from "new ideas" and "education". They will become nothing more than minimum wage workers and fodder for our prisons and welfare system. We already see that happening.