There is no doubt history repeats itself, human nature does not seem to have evolved as much as the physical improvements needed for survival. Our government certainly has never let a good crisis go to waste; seems to even have generated some just for shits and grins.
This time in our experiment with democracy seems particularly at risk and I wonder if cooler and smarter heads will prevail and the majority can get some of the haters and war mongers spewing fear and loathing under control.
and then popped up on the music feed and all that 60's Vietnam era music came to mind.

I have a big problem with the idea of how certain people (personas) shape history. To me history especially one that deals in a dramatic shift, like war are determined by the social and especially the natural environment. It is said that if people are secure they don't want to upset the applecart and promote change. It is when they feel threatened that things start to change. Invariably an individual will come along to ignite that change but often times it only takes one person speaking out. Also, politicians use history in ways that suit them so if any lessons come from someone with something to gain it probably has been altered.

Is America old enough to extrapolate 80-90 cycle patterns?

It looks to me like it's a struggle for individual rights and freedom. If we leave out the fight for black equality, a long struggle now somehow integrated into the mainstream, maybe it could be said that the fight is going on noticeably since the 1960s. It is curious that the struggle for rights for the disenfranchised is carried out in social media and public venues by disallowing the rights of the supporters of the social structure to even speak up and defend their positions. Somewhere in all this, the idea must exist that everybody can have an equal share in freedom but it seems to really mean the right to be free to hold one opinion, which is a little bit like the proposition they told us God gave to Adam and Eve.

I'm stuck on the crisis in American history part. Does this mean that the same thing does not happen in other countries?

Didn't Santayana paraphrase that as: Those who don't remember the past are condemned to repeat it?