A friend has asked me to compare what we're going through now to other political crises you've experienced in the US. An interesting suggestion. So here goes ...
I was born at the end of 1945, so my adult family members went through WWII and are widely considered to be members of the 'greatest generation'. As in all wars, the crisis of WWII led to the nation running roughshod over the Constitutional rights of some Americans, notably the Japanese-Americans. Since I have no direct experience with WWII, I can't say much about that crisis, except to note that the suspension of at least some Constitutional rights has happened several times in the history of the US wars. I've read a lot about the Civil War, WWI, and WWII and the associated politics, but that doesn't make me a proper historian.
I was barely old enough to have much grasp of the Korean War, especially early on. This was the opening conflict of the Cold War. I remember seeing news from the 1953 peace talks at P’anmunjŏm and how happy everyone was that the war had ended - with an armistice (not a peace treaty). Technically, the Korean War never ended; North and South Korea are still at war. This war was the time of Joe McCarthy and the House Unamerican Activities Committee - he was characterized by a sort of crypto-fascist extreme nationalism. McCarthy overreached his mandate and was repudiated for his extremist views.
When I was in junior high, I had a Social Studies teacher who was a rabid anti-communist. He harangued us with frequent fear-mongering rants about the dangers of soviet and Chinese communism. This fear caused me to do some investigating on my own, so I literally read dozens of books about soviet communism. I wanted to understand why the soviets hated us so much, even as we were being taught to hate them. The Cold War went on for many more years, and I remember being drilled about "duck and cover" in school in the event of a nuclear war. I was raised at a time of intense suspicion, fear, and paranoia based on what I was told about the soviet threat. You lived every day of the Cold War under a constant threat of nuclear annihilation. My readings convinced me of two things: 1. the Russian people didn't really hate us, and 2. most Americans were ignorant about Russian history. Like many wars, the Cold War was a clash of ideologies, not between ordinary people. All of us were in constant danger of being killed in a nuclear war - for something as foolish as a clash over ideology.
The Cuban Missile Crisis in 1962 occurred when I was in high school. It was to take the world to the brink of a nuclear holocaust, and that fear was quite real for many days. JFK and Nikita Khrushchev finally negotiated a settlement that ended that terrifying threat. To us, it seemed the evil soviets had been forced to back down. The real negotiations were not at all consistent with that perspective, but both populations were fed a bogus narrative that was politically expedient for the politicians who had threatened our very existence.
The Cold War became hot again when we engaged in the Vietnam War - a tragic error in judgment by the US (including choices made by JFK and then LBJ). Like the Korean War, the Vietnam War was not declared formally - in the jargon of the age, it was described as a "police action" fought not by police but by the military forces of the US. Ostensibly, it was a matter of "containment" of communism - the so-called "domino hypothesis" that if Vietnam fell to communism, that evil ideology would spread across all of southeast Asia and on to the rest of the world. By the time when the US was defeated in that war (after winning most of the battles decisively), it had divided the nation. Conservatives felt we should have "won" the war by any means possible (even though there was no clear way to define what "winning" such a war would mean), but toward the end of our Vietnam troop presence, so many Americans were so opposed to the war that LBJ chose not to run for re-election. The anti-war riots during the Democratic National Convention in Chicago happened under eyes of the media - as the chant went "The whole world is watching!" I watched the TV coverage of that event. Nixon (before he was forced to resign as a result of the Watergate political scandal and subsequent cover-up) tried to cast our departure from Vietnam as "peace with honor" ... but it was a defeat, pure and simple.
I will have only a little to say about the civil rights movement as it had developed around the time of the early beginnings of the Vietnam War. It's evidence of another source of division in America. White privilege made much of that divisive clash invisible to me: I was raised in a lily-white bubble, so I had virtually no understanding of what was happening at the time. One couldn't help but feel ashamed of what was happening to black people in this nation, as shown nearly nightly on TV. My time in the Army (including in Vietnam) began a process of clearing away the white foam that so limited my comprehension. For the very first time, in that war, I actually talked with and worked with and played with black Americans That clearing process continues to this very day, as racism has not ended in America - not by a longshot!
My nation has a long history of cyclic swings of the political center - sometimes left, sometimes right. My perspective is that the conservative v. liberal struggle has changed from having a spirit of mutual respect and compromise for mutual benefit, to become so divisive and downright dirty that many people have grown deeply disillusioned with our government. The government is paralyzed by uncompromising political ideology conflict. It's become acceptable to propose unconstitutional policies in the political arena to gain political ascendancy. Gerrymandering and voter disenfranchisement have solidified the dominance of the conservatives (GOP) in Congress. Many people have lost faith in the principles laid down by our nation's founders. Many are willing to be racists, to be chickenhawks (willing to send our troops into battle but unwilling to fight in those battles), to murder those who violate their personal sense of what is moral.
We've gone to war several times on the basis of an exaggerated fear for the threat posed by terrorism - which concedes victory to the terrorists. Fear is their goal, and when we give in to that fear, they celebrate. The reality of our continuing wars is what former President Eisenhower warned about: those in the military and those engaged in war industries coming to dominate policy decisions regarding going to war to maximize profits. In no war in my lifetime has there been a credible threat to freedoms in the USA against which to defend on foreign soil. The biggest threat to American freedoms is neither foreign nations nor terrorist groups. Rather, the threat to our freedoms comes mostly from the willingness of people to give up their freedoms for the illusion of security. We seem to be able to tolerate NSA monitoring of email, social media, phone conversations without any warrant or probable cause. The politicians passed the Patriot Act, ostensibly to combat terrorism. We operate a prison in Guantanamo that is manifestly illegal, and contrary to American law as it is supposed to be practiced. We have employed the discredited and widely disavowed practice of torture to obtain information from prisoners of our wars.
My readings of history have shown me that many Americans are inclined to believe that we somehow are immune to becoming a fascist police state, an oligarchical kleptocracy, or even a theocracy. I see no evidence to support that delusional belief in American Exceptionalism. Quite the contrary, in fact. I see evidence we're quite vulnerable to dictatorial fascism. The belief that "it can't happen here" is pervasive - it opens a wedge in which a demagogue can enter at a critical time and win a power battle that results in a fascist cult of personality. The rest will follow ...
This brings me finally to the Trump regime. Despite what my stubborn conservative friends believe, it can happen here. We're facing a threat I see as quite comparable to that of Wiemar Germany in the years leading up to Hitler's appointment as Chancellor by Hindenburg in 1933. Within a short time, Hitler pushed through legislation that gave him absolute power, and the rest of the tragic story of WWII follows from that. Note that Hitler never actually won a democratic election - whereas we Americans actually have elected a pathological liar and narcissist who's already attacking the foundations of our secular, Constitutional democracy. From where I sit, the threat is more frightening to me than anything I've ever experienced personally. No, Trump has yet to suppress dissent with violence and he has not yet been granted dictatorial powers. There are as yet no concentration camps. If Trump's policies are fully implemented, it seems all too likely that where he and his GOP cronies are taking us is into a fascist cult of personality. I hope the American people will come to their senses and repudiate this Trump regime. Destroying our Constitutionally-based rule of law is not a sensible path toward improved governance by our elected officials. As I see it, the Trump regime poses the greatest threat to American democracy short of a full nuclear exchange.