From early disagreements between various Founding Fathers on hot button issues like the Sedition Act, central banking and standing armies, to epic and disastrous conflagrations like the Civil War, America has never been "of one mind" on everything.

Overall, though, the longstanding assumption is that even when we slip and fall into disarray Americans will find common ground and move on towards the future together.  It's a nice sentiment, but what if this ideal no longer applies?

There are some people that argue there was never a golden era for the US; that we've always been destructive, or exploitative or "imperialist." Of course, it's very easy to examine any given time period through the lens of modern sensibilities and pass judgment. How we would do things today is not necessarily how we would do things yesterday. We can't easily condemn the men and women of the past without at least recognizing that we will probably never see the issues of their day from their perspective.

The political left is the most egregious violator of this principle. They have a bad habit of trying to rewrite history according to their current ideological cultism and applying their taboos to time periods when civilization had very different views on how to function. The progressive philosophy is partially rooted in "futurism"; the idea that all old ideas and ways of doing things must be abandoned to make way for new methods. In other words, they think everything "new" is better and must be embraced.