In the early months of 1968, Minnesota Senator Eugene McCarthy campaigned for the Democratic presidential nomination on an anti-war platform and generated surprising support in the wake of the Viet Cong's Tet Offensive, which stunned and debilitated US forces. The troubles in Vietnam undermined President Lyndon Johnson, who had been elected in an historic landslide victory four years earlier.
Johnson exited the race in late March, soon replaced by his vice president, Hubert Humphrey. The ensuing battle between two liberal favourites, McCarthy and Senator Robert Kennedy, ended in early June when the latter won the California primary and was assassinated in Los Angeles that same night.
Ten weeks later, with political tensions peaking, Chicago welcomed the Democrats' five-day nominating convention to the International Amphitheatre, a squat brick stadium about six kilometres south of the city's Loop, or downtown. But the real action occurred a few kilometres north, in Grant Park, an expanse of green wedged between Lake Michigan and the massive Conrad Hilton Hotel, headquarters of the press and the candidates' campaigns.
On the third night of the convention, a Tuesday, a mass of anti-war demonstrators - militant hippies (also known as "yippies"), college students, artists and writers like Allen Ginsburg and Jean Genet, along with priests from a nearby church - had been tear-gassed and chased out of Lincoln Park, a few kilometres further north along the lake. Vanquished but invigorated, the group marched downtown.
By 4am Wednesday, some 5,000 had gathered in Grant Park, "a revolutionary army of dissenters and demonstrators and McCarthy supporters and tourists ready to take a crack on the head", the novelist Norman Mailer writes in his coverage of the event for Harper's magazine (which later became part of a book, Miami and the Siege of Chicago).
At daybreak, National Guardsmen arrived in khaki uniforms with helmets and rifles. Army lorries and massive barbed-wire-hooded jeeps roared up Michigan Avenue as police fenced off sections of the park. The crowd swelled to as many as 15,000 after word spread that Mayor Richard J Daley had granted a permit to assemble, though not to march.
Many were chased off by tear gas and occasional police forays into the crowd throughout the day. But as twilight approached, the 5,000 remaining protesters began to march south down Michigan Avenue towards the convention. Police halted the marchers in front of the Hilton, penning them in on three sides.
"There," writes Mailer, watching from his room on the 19th floor, "the stationary march was abruptly attacked. The police attacked with tear gas, with Mace, and with clubs … they attacked like a scythe through grass, lines of 20 and 30 policemen striking out in an arc, their clubs beating, demonstrators fleeing … The action went on for 10 minutes, 15 minutes, with the absolute ferocity of a tropical storm."
Dispatches recount police beating teenagers in the street until blood streamed down their temples, keeping doctors from the injured and assaulting and arresting idle observers. Rick Kogan, author, radio personality and columnist for the Chicago Tribune, was 16 years old and answering phones for local reporters at the Hilton at the time.
"Here I am, inside, behind that line, at a gathering of thousands of people who looked very much like me, all of whom were agitated beyond words," he recalls. "You could sense the fear among the cops too. They were young, some the same age as the protesters."
The convention resumed, but with a darker hue. Announcing his party's nomination of Humphrey a couple hours after the melee, Connecticut Senator Abraham Ribicoff spoke of "Gestapo tactics on the streets of Chicago", drawing immediate condemnation from Mayor Daley, sitting in the audience.
South Dakota Senator George McGovern, who would four years later become the Democratic presidential candidate, called the Michigan Avenue crackdown a "bloodbath", saying he had "seen nothing like it since the films of Nazi Germany".
But the rough stuff in Chicago shouldn't have come as a shock. Months earlier, during riots across the city's South Side in the wake of the assassination of Martin Luther King, Daley, a long-serving Democrat, had given "shoot to kill" instructions to his police. "Chicago is a very conservative place," says Kogan. "Most Chicagoans, working-class Chicagoans, were on Daley's side on this. They did not think of it as a police riot. They thought of it as a battle between long-haired hippies and the establishment. Most Chicagoans said, 'Good. Bang 'em around. They shouldn't be doing this'."
Haskell Wexler's 1968 film Medium Cool, a hybrid documentary-narrative that climaxes at the convention, captures the Grant Park clashes with visceral immediacy. In one scene, protesters shout a cautionary mantra more appropriate for the age of YouTube and Twitter: "The whole world is watching."
What the world saw that day was the end of an era.
"The Democratic Party had here broken in two before the eyes of a nation," writes Mailer. Meanwhile, a few weeks earlier in Miami, the Republicans held a convention that seemed to take place in a calmer and more confident universe.
Reporting from the "the dullest convention anyone could remember", Mailer sees "an American faith, a belief, a mystique that America … was the world's ultimate reserve of rectitude, final garden of the Lord".
The former vice president Richard Nixon won the nomination, campaigned on a promise to restore law and order to the nation's cities and clobbered Humphrey in the November election. The progressive New Deal coalition that had held a near-stranglehold on the US presidency since the early 1930s ended, starting an era of Republican dominance.
Much like their contemporary Arab counterparts, the liberals who led the upheaval did not come to power, but were beaten back and voted down.
On the streets of Chicago and in the decades that followed, the hippies lost and conservatives won, reorientating a nation.
In his coverage of the convention, Mailer strolls the city's Loop, past "old department stores, old burlesque houses, avenues, dirty avenues".
Today, Chicago's downtown is filled with boutique hotels with swanky rooftop bars, buzzing cafes and lunch spots and top retailers like Macy's, the Disney Store and Godiva Chocolates.
Next to the Hilton, which still welcomes guests to South Michigan Avenue, stands a busy Starbucks and one of the city's finer tapas restaurants.
Most of the economic revival seen here and in other American cities occurred during the Republican-dominated boom years that began in 1980.
In his new book, Twilight of the Elites, political commentator Christopher Hayes writes, "'Meritocracy' was adopted as the perfect name for the American system of testing, schooling and social differentiation that, in the wake of the social upheaval of the 1960s, would produce a new more diverse elite to replace the inbred Eastern WASP establishment."
Barack Obama - lower-middle class, of mixed heritage, raised by a single mother and his grandparents to become leader of the free world - is the definitive success story of the American meritocracy. As he heads to the podium for his second inaugural address, in the wake of a lengthy recession, talk of a conservative collapse and a liberal revival has grown.
The poor have overthrown the one per cent, the thinking goes, ending the hawkish, trickle-down age of Republican presidents Ronald Reagan and George W Bush and marking a new liberal moment. "I went to bed last night thinking we've lost the country," the right-wing radio talk show host Rush Limbaugh said the morning after the election. "I don't know how else you look at this."
The yippies would certainly be cheered by America in 2013. It's legal to smoke marijuana, without a prescription, in Washington and Colorado. Gay couples can now marry in a dozen states, with the US Supreme Court set to hear arguments on the subject.
The US, out of Iraq and leaving Afghanistan soon, has developed an apparent distaste for war after those pricey misadventures pushed the country near bankruptcy.
Obama's re-election marked the first time in decades that a candidate campaigned on a call for lower defence spending and won.
After the Newtown shootings, support for gun control is at an all-time high. And after Hurricane Sandy, local and national government bodies are taking the threat of climate change seriously.
Some of these developments may be more about the arc of enlightenment than the success of a political agenda, but looking ahead, the demographics favour Democrats.
America's white population is stagnant, while the numbers of liberal-leaning minorities are increasing. Cities, where people tend to be more progressive, are growing faster than suburbs, while generally hide-bound rural areas are dying.
That's not to say all is well. What liberals seem to have gained during their 40 years of political exile is a better grasp of American meritocracy. A primary tenet of the liberal agenda is equality, or at the very least equal opportunity. Yet America has never been so unequal, its elites never so elite.
Since 1989, income inequality has increased in 49 of 50 states. For the top fifth of earners, income has increased 17 per cent over that time, while dropping two per cent and seven per cent for the middle fifth and the bottom fifth, respectively. Today, 40 per cent of all wealth accrues to one per cent of the American population.
And they are not all financiers and celebrities. Washington is redistributing wealth to itself. The average income ratio between the top five per cent of Washington, DC, households and the bottom 20 per cent is 54 to 1, up from 39 to 1 in 1992 and wider than all but two major cities. From 1984 to 2009, the median net worth of American households held steady while the net worth of members of the House of Representatives increased more than two and a half times.
At the same time, social mobility has fallen below that of Europe. The main problem is a test-reliant education system in which pricey tutors and test prep mean the gains for richer kids far outpace those of lower-class children. A Stanford University study found the achievement gap between rich and poor students on standardised tests is 30 to 40 per cent wider than it was 25 years ago.
Now a cottage industry of liberal worry about the future of America has begun to emerge, even amidst the hope of a second Obama term and political victories to come. Just after the election, New York Times columnist Timothy Egan wrote that the experiment of America as a "democracy that is not divided by oligarchical gaps between rich and poor is still hanging in the balance".
In a Foreign Affairs magazine essay entitled Can America Be Fixed?, Fareed Zakaria points to Americans' lowest-ever levels of trust in their government - 19 per cent in 2010, down from 76 per cent in 1964 and 30 per cent in 2008. "Is there a new crisis of democracy? Certainly, the American public seems to think so," Zakaria writes. "This time, the pessimists might be right."
In his book, Hayes links this lack of governmental trust to repeated failures from American institutions over the past decade, citing Hurricane Katrina [we could add Sandy], the housing bubble, the sins of the Catholic Church, the Iraq War, Enron, Lehman Brothers, the financial crisis and more.
Despite this near-total lack of accountability, American authority figures have been able to not only maintain their position but also pass on their status - with each generation less qualified than the last. "As American society grows more elitist," Hayes writes, "it produces a worse class of elites."
All of which brings us back to Chicago in 1968. On the last day of the convention, Democratic Party organisers screened a film memorialising Robert Kennedy. "It was incredible to think of him as president," Mailer writes, "and yet marvelous, as if only a marvelous country would finally dare to have him."
Four years ago, progressives heralded the Obama presidency as a new moment for America, the beginning of a liberal rebirth, a return to the glory days of Franklin D Roosevelt and John F Kennedy. But it hasn't proven so marvelous. Wall Street has still not paid for its mistakes, inequality continues to rise and institutional failure rages unchecked. Meritocracy has failed.
Democrats may dominate the elections to come. The government may tilt toward a liberal agenda. But America will remain in thrall to a powerful elite, red and blue and able to fail repeatedly yet stay on top, little concerned with the tribulations of the lower classes that result from those failures.
The US seems not so dissimilar from so many developing countries, in which a small, empowered minority lord over the disadvantaged working masses. In the years to come, Hayes envisions not a revolution of the proletariat, but rather a broad coalition of radicalised middle classes - the Tea Party, Occupy Wall Street, other groups - coming together to call for accountability and effect change.
It probably won't happen on the streets. Observers expected a great deal of dissent at the Nato summit in Chicago last May, but a massive show of force quelled the demonstrations. "There was no cohesive coalition," says Kogan. "It never coalesced into any kind of group. The protesters didn't seem motivated enough."
A half century ago, liberal ire spiked over just a handful of years, via historical moments in full public view: assassinations, riots, tens of thousands of Americans killed in a questionable war. Today's crises - of inequality and institutional failure - seem quieter, more insidious. Or perhaps America has simply grown too gluttonous for revolution. Maybe a second Obama term tastes too much like victory to progressive Americans.
Either way, it's simplistic and naïve to say that the protests of 1968 failed. That great wave of righteous frustration helped move the country forward. Dislodging or at least discomfiting today's elite will require similar momentum, and probably more crises to come.
David Lepeska is a freelance writer who contributes to The New York Times, Financial Times and Monocle, and previously served as The National's Qatar correspondent. He lives in Chicago.