The year 1968 — whose blood-splattered, baton-swinging 50th anniversary party is about to peak this Memorial Day weekend with the 4-hour 1968 documentary on CNN — was truly a season for the good, the bad and the ugly. I mean that literally — Hugh Montenegro's version of the theme song to the hit spaghetti-Western, The Good, the Bad and the Ugly was all over the AM radio that spring, with its unforgettable ocarina opening and its "rep rup rep rup" chorus. But figuratively, the Ugly walloped both the Good and the Bad in the wider world of 1968 by a big margin.

It's easy to forget that. Those round, tinted spectacles that the likes of John Lennon were wearing in 1968 were the ultimate rose-colored glasses, after all. And so the purple haze of nostalgia can cling to glib Time-Life-infomercial-style memories of the halcyon daze of the decade that changed America — bright tie-dyed colors illuminated by a strobe light and pulsating to the fuzzy guitar riffs of Jimi Hendrix and Cream. "I think it's so groovy now," an act called Friend & Lover sang in the summer of 1968, "that people are finally getting together."

The song was pure wishful thinking. Ask anyone who lived through 1968 — even those of us who were bright-eyed grade-schoolers then — and we can tell you that the year was experienced in real time mostly as hell on earth. No, you really didn't need a weatherman to know which way the wind blows, not when these things were in the air: The Tet Offensive, with planeloads of American-flag-draped caskets flying home from Vietnam every week. The assassinations of Robert F. Kennedy and Martin Luther King Jr. — the latter followed by days of urban rioting that claimed dozens of lives. And student and youthful uprisings that were put down with violent force — from Columbia University and Chicago here at home to the streets of Mexico City and even Czechoslovakia, where Soviet troops crushed Prague's spring awakening.

If you didn't experience 1968 as a sentient human being, or if you were looking out the window that day in 10th-grade history class, you would probably be shocked by the CNN documentary. It was shocking. It felt like the End Times. Such a momentous year would have sparked a flurry of anniversary books, articles, and TV specials under any circumstance. But 1968's 50th birthday bash has arrived with unexpected resonance, because in 2018 it seems to many people like the world is crashing down all over again.

Indeed, America's blend of paranoia and angst seems remarkably similar to the late 1960s, albeit without the great musical soundtrack, and a different storyline — a corrupt and autocratic government, but minus war and bloodshed in the streets…so far. The irony is that you can draw a straight line and see how the war for America that essentially began in 1968 brought us to the current battlefield that is 2018.

The legacy of 1968 is complicated. It was the start of many good things — a freer spirit of expression in the arts and fashion, a movement for female empowerment, gradual (albeit too gradual) gains for African-Americans for other non-whites, and for the LGBTQ community. But politically, the legacy of 1968 is largely backlash (highlighted by that year's election of Richard Nixon on a "law and order" platform) and repressive moves such as "the war on drugs" and a regime of mass incarceration.

And here's the ultimate irony: Two things happened in so-groovy-now daze of 1968 that paved the way for the authoritarian presidency of Donald Trump.

Bummer, man.

No one would have been more surprised than the 22-year-old Donald Trump who roamed the streets of Philadelphia in the spring of 1968. A mediocre transfer student at the University of Pennsylvania's Wharton School, Trump's only noteworthy achievement of his late-'60s stint in Philly was convincing his classmate, the glamorous future Hollywood star Candice Bergen, to go out on a date with him (don't worry…nothing happened). The 20-something, bone-spur-plagued Trump was bound not for 'Nam but for New York, where he and his dad would be devoted to violating the one landmark liberal law of 1968, the Fair Housing Act. It's doubtful that The Young Donald had any inkling of the changes in the political landscape that set the stage for a demagogue to rule America — let alone that the demagogue would be him.

The paradox of 1968 and Donald Trump comes into focus if you read the defining political book, so far, of 2018: How Democracies Die, by Harvard professors Steven Levitsky and Daniel Ziblatt. The book makes the case that in the 21st Century democracy is less likely to collapse through a dramatic coup than through a slow erosion of established norms such as a free press, voting rights or an independent judiciary — something that's happened with elected governments from Venezuela to Hungary and is happening right now in the United States.

In America, the chaos of 1968 hacked at our democratic norms and traditions in a couple of ways. One of the changes was very specific but critical. In August 1968, thousands of antiwar demonstrators who were in the streets protesting the Democratic National Convention as it voted down an anti-Vietnam-War-plank were clubbed and bloodied by cops in what an investigative panel later called a "police riot." The mayhem was captured by the newfangled medium of live TV (as memorialized by the protesters' famous chant, "The whole world is watching!") and was largely blamed for nominee Hubert Humphrey's narrow loss to Nixon that November.

The disaster inspired Democrats to change the rules — so that going forward the vast majority of convention delegates would be chosen not by party bosses but by the people, in state primaries. The idea of making presidential nominations so much more democratic and thus eliminating "the smoke-filled room" was wildly popular — so much so that Republicans adopted similar rules. What could go wrong? Well, as Levitsky and Ziblatt chronicle, party elites lost their ability to screen out candidates who appealed to voters through racism or other ugly strains of populism. Leaders in both parties had once thwarted the worst populists like George Wallace or the anti-Semitic industrialist Henry Ford (whom many wanted for president in the early 1920s). But GOP elites who scorned Trump in 2016 had no way to stop him.

"In short, primaries limit party leaders' ability to screen out extremists and demagogues," co-author Levitsky told me in an email interview. "This hardly guarantees that demagogues will win the nomination, but it leaves parties more vulnerable—especially to celebrity outsiders with a lot of media exposure and name recognition.  And that's what happened in 2016."

The other important thing that happened in and around 1968 was the intense political polarization of America — an event that had a lot to do with the issue that has hung like a millstone around the nation's neck since its founding, which is race. Although it gets relatively short shrift amid all the crazy things that happened in 1968, the other event that's had a remarkable long-term impact is the urban rioting that exploded after MLK was assassinated in Memphis on April 4, 1968.

The reaction to the riots — white flight to the suburbs and support for Frank Rizzo-style policing on steroids — created a political momentum for white backlash. Nixon, a very smart if ultimately immoral politician, saw this and jumped on it — naming the combative Spiro Agnew his vice president as a reward for his tough stance on Baltimore's black rioters, and making "law and order" the theme of his campaign. (As dramatized in this famous campaign ad.)

Nixon's ensuing "Southern Strategy" to woo white voters alienated by the Democrats' support for civil rights legislation worked. As Levitsky and Ziblatt note, the much-revered era of bipartisanship and comity in American politics was largely built on a compromise that involved both parties suppressing black demands for equal rights for 100 years, beginning with the Compromise of 1877 that ended Reconstruction and cleared a path for the rise of Jim Crow segregation, and continuing with New Deal programs that largely benefited whites. The politics of 1968 blew that up — the GOP increasingly became the party of white working-class backlash as Democrats became more of a party for non-whites and professional-class whites who at least voiced support for civil rights.

"Now the Republican Party is unambiguous home of the white Christian voter, the rural white voters, the racially conservative white voters, and if you will, the angry white voter," Levitsky told me. "This is an electorate that is experiencing status decline in a society marked by growing racial equality and ethnic diversity.  It's a group that is open to populist white nationalist appeals."

In 2016, Trump took this 50-year gathering storm to its inevitable conclusion. The so-called coded "dog whistles" on welfare fraud or crime that Republicans had used to make racial appeals in the 1980s became a bullhorn in the tiny hands of The Donald, who screamed about Mexican rapists and "The Wall" and won primary after primary. At the 2016 GOP convention in Cleveland, Trump made an appeal to "law and order" that was ripped almost word for word from the Nixon playbook, and today he tries to flog the issue of black athletes protesting police brutality during the National Anthem much as white rage burned about the Black Power salutes of Tommie Smith and John Carlos at the 1968 Olympics.

It's impossible to watch 1968 or the myriad other 50th anniversary productions without thinking about what William Faulkner wrote, that "the past is not dead. It's not even past." The sad truth of 1968 is that while America didn't implode — as many feared while watching the violence and assassinations in real time — the tumult of that time may have launched the nation into a slow-motion political near-death spiral, and I'm clinging to the word "near" here. At least we can still enjoy the amazing music as we ponder what a long, strange and too-often bad trip it's been.