In this year’s race for the White House, American voters nearly had to choose between a fake Republican and a fake Democrat. Billionaire real-estate developer and reality TV star Donald Trump thumped his opponents in the Republican primary after spending his entire adult life as a boorish Democrat. Bernie Sanders nearly grabbed the Democratic nomination from Hillary Clinton despite spending his entire Senate career as an independent socialist, well to the left of the Democratic Party.

Sanders and Trump are flip sides of the same populist coin. At a glance, they appear to be ideological opposites. Whether incidentally or on purpose, Trump appeals to the so-called alt-Right—the ragtag crew of white nationalists, xenophobes, anti-Semites, Muslim-haters, neo-Confederates and “birthers.” Sanders, meanwhile, appeals to what might be called the alt-Left—assorted Marxists, “safe-space” activists, cop-haters, anti-Zionists, anti-vaxxers, and blame-America-firsters. Look closer, though: both candidates are populist anti-elitists who claim that “the system” is “rigged.” Both promised to kick over the garbage cans in Washington. Both railed against money in politics. Both claimed that immigration depresses working-class wages. Isolationists in economics and in war, they bucked mainstream Republicanism and Clintonism. And, as Troy Campbell put it in Politico earlier this year, they are both “enabling dissenters” who have “legitimized for discussion ‘fringe beliefs’ that millions of Americans beforehand had been unsure of or too shy to fully embrace, but nonetheless felt strongly about.”

Trump mounted a successful insurgency against the Republican establishment; his rise has ignited fratricidal warfare in the GOP, and no one knows where it will end. The Democratic Party establishment had better luck battling against the Sanders insurgency, putting it down, at least for the time being. But Hillary Clinton is the standard-bearer for a status quo that huge numbers of people on both sides of the political spectrum can no longer stand. In the years ahead, Sanders’s overwhelmingly young supporters will only become more numerous and engaged. If they pull off a hostile takeover someday, the Democratic establishment can’t say that it didn’t hear the warning shots—they rang out loud and clear at the Democratic National Convention in Philadelphia this past summer.

If I didn’t know better, I would have sworn that Philadelphia was ground zero for an anti-Clinton insurgency. When I went downtown to pick up my press credentials the day before the convention, furious Sanders supporters swarmed the sidewalks, blocked streets, snarled traffic—and guaranteed overtime pay for local police officers. They chanted, “Hell, no, we won’t vote for Hillary!” They carried placards and signs. CAPITALISM HAS OUTLIVED ITS USEFULNESS, read one. I saw “Bernie 2016” T-shirts everywhere and not a single Hillary shirt. Even without the T-shirts, the Sanders activists were easy to spot. They were the ones who looked like they’d just eaten a sack of lemons. Right in front of Philadelphia’s gorgeous City Hall—it’s the largest in the United States and could fill in for the Paris City Hall in a pinch—a Sanders crowd impersonated a Donald Trump rally, chanting “Lock her up!” and carrying “Hillary for Prison” signs.

Traffic ground to a standstill. My taxi driver ranted and raved, banging on the steering wheel over and over again. He called me “sir,” but I nevertheless felt guilty for being one of tens of thousands of outsiders who had effectively colonized his city and made it nearly impossible for him to do his job. “I’ve been a Democrat my entire life,” he said, “but this year I’m voting for Trump.”

At first glance, it appeared that nearly everybody in Philadelphia hated Clinton, until I saw that the city center was packed with DNC volunteers. They, too, were easy to spot. All wore the same light-blue T-shirts reading “Democratic National Convention” on the front and “Ask Me” on the back. I chatted with some of them, partly because I needed directions and also because I wondered what they thought of the protesters. They made no secret of their contempt for “the Bernie people,” as they called them.

Sanders activists weren’t the only ones taking to the streets that week, hoping for coverage from the journalist hordes. Even more extreme leftist demonstrators gathered as close as they could to the delegates. They screamed, “Go home, F*** Hillary,” and burned American and Israeli flags. Some shouted “Long live the Intifada!,” referring to the wave of Palestinian suicide-bombers who exploded themselves on Israeli buses and in Israeli cafés in the early 2000s.

Philadelphia native Erica Mines led a protest march against police brutality, yelling, “Hillary Clinton has blood on her hands.” One of the signs in her rally read, “Hillary, Delete Yourself.” “Hillary, you’re not welcome here,” read another. “I need all white people to move to the back!” Mines thundered. “This is a black and brown resistance march! If you are for this march and you are here to support, you will take your appropriate place in the back!”

Those whose favored candidates lose a primary election often feel bitter toward the winner, but the Sanders supporters were furious at the entire Democratic Party for allegedly stealing the nomination. Just two days earlier, WikiLeaks had dumped a trove of e-mails onto the Internet, probably acquired from hackers backed by Russian intelligence, that proved that party elites had had it in for Sanders all along. Democratic National Committee chair Debbie Wasserman Schultz had just resigned her position, and at another rally downtown, Sanders supporters chanted, “Debbie is done!”

Sanders and his supporters had a right to be angry, but it doesn’t matter what the establishment wants if the voters want something else. Just look at the GOP. The Republican establishment went after Trump with hammer and tongs, but primary voters put him over the top, and their second choice, Ted Cruz, is another antiestablishment crusader. Establishment pols can’t force voters to do what voters don’t want to do.

One of the signs in the rally read, ‘Hillary, Delete Yourself.’ ‘Hillary, you’re not welcome here,’ read another.

The Democratic establishment didn’t have to fight as hard as their Republican counterparts. If Sanders had been ahead during the primary season instead of perpetually lagging behind, the Democratic establishment almost certainly would have blasted him with both barrels, but a Sanders win never looked likely. He won small, overwhelmingly white, states; but Clinton won larger, racially diverse, states in one landslide after another, not because the system was rigged but because Sanders came across to most nonwhite voters as an alternative novelty candidate. The establishment could hold its collective breath and ride out the storm.

The 2016 Democratic National Convention actually sprawled across two main venues: downtown, at the Philadelphia Convention Center, the place for untelevised (and unscripted) meetings and panel discussions between delegates and other party officials; and, a few miles south, the Wells Fargo Center arena in the South Philadelphia Sports Complex, where party big shots delivered speeches in front of the television cameras.

On the first day, I headed for the Convention Center for the morning meetings before the televised portion from the Wells Fargo Center kicked off in the late afternoon. On my way inside, a man on the corner handed me a pamphlet for the Communist Party. Everyone who went in got one. The DNC couldn’t keep Communists away from the perimeter any more than it could keep the angry Bernie legions away.

I tossed the Communist propaganda into the garbage and sighed, relieved that I could put the heat, the anger, the yelling, and the political whack jobs behind me. No one could set foot in the convention center without credentials, and the air inside the building was 30 degrees cooler and 50 percent less humid. Still, 100 percent of the T-shirts inside the Convention Center had Bernie Sanders’s name on them. Had I been whisked into an alternate universe where Hillary Clinton lost the primary? Were the halls of the Republican National Convention in Cleveland the previous week filled with people wearing Ted Cruz or Marco Rubio T-shirts? Not a chance.

After a few minutes, I figured it out. Clinton supporters didn’t wear T-shirts. They dressed professionally. Some sported a small Hillary button next to an American flag pin, but they otherwise looked like managers and corporate executives. Sanders supporters looked like hipsters who’d just spent the night on somebody else’s couch, and they appeared to be, on average, about 20 years younger than everyone else.

The data support my observations. Young primary voters overwhelmingly pulled the lever for Sanders, while older voters went overwhelmingly for Clinton. In New York, for instance, Sanders beat Clinton among voters under 30 by a whopping 53 points, yet Clinton still carried the state by 16 points.

Those aren’t the only political data that set young millennials apart from their elders. According to an exhaustive report by political scientists Roberto Stefan Foa and Yascha Mounk in the Journal of Democracy, young people today are considerably more authoritarian and antidemocratic by attitude and temperament than any other generational cohort, especially baby boomers. Only 30 percent think that it’s “essential” to live in a country with a democratic system of government, and a terrifying 24 percent actually think that a democratic system of government is a bad thing. Only 32 percent of millennials think that it’s “absolutely essential” that “civil rights protect people’s liberty.” According to a Pew Research Center report, 40 percent of millennials want the government to ban “offensive” speech.

“The decline in support for democracy,” Foa and Mounk write, “is not just a story of the young being more critical than the old; it is, in the language of survey research, owed to a ‘cohort’ effect rather than an ‘age’ effect.” In other words, millennials are likely to carry these ideas and attitudes with them for the rest of their lives. Their contempt for free speech is a stunning reversal of the Free Speech Movement on university campuses in the 1960s led by young boomers who fought hard to topple institutional censorship. Many of today’s young adults, by contrast, want to impose institutional censorship—not just on college campuses but across the nation.

I slipped into a Small Business Council meeting, attended by perhaps 150 people along with a handful participating in a panel. I saw plenty of Hillary buttons and small American flag pins. Nobody wore a Bernie T-shirt. In fact, no one in that room wore any kind of T-shirt. This was a room full of professionals, not unemployed college kids. It had the look and feel of a Rotary Club meeting.

By contrast with the unglamorous and somewhat dreary discussions going on at the Convention Center, the program at the Wells Fargo Center was a pep rally and commercial for TV. The arena is far removed from the city center, in a gigantic ocean of parking lots near two other stadiums. Federal and local authorities set up a perimeter a mile and a half away, manned by police officers who ensured that everyone who passed that point had the proper credentials. Protesters and would-be assassins could not get any closer without being arrested—or shot.

Those of us with credentials had to walk for a half-hour through blazing sunshine, without shade. Temperatures pushed 100 degrees with 100 percent humidity. The air was as heavy and hostile as Baghdad’s. My clothes stuck to my skin. I could smell the tar bubbling on the asphalt. I envied, for once, the Sanders delegates in their soft shoes and T-shirts.

Transportation Security Agency (TSA) and heavily armed Secret Service agents manned metal detectors. Black jeeps with the words “Counter Terrorism” stenciled on the sides roamed inside the perimeter. Helicopters flew overhead. Snipers took up positions on the stadium roofs. I haven’t seen so much security anywhere in the world except on military bases in Iraq.

As I took my seat on the first day, a color guard with the Veterans of Foreign Wars brought American flags onto the stage for the national anthem. Young Bobby Hill belted out a pitch-perfect “Star-Spangled Banner,” and midway through, many in the audience sang along. It was a genuinely moving moment, and it was completely unscripted.

The flags were taken offstage and the script got going in earnest, but some people refused to stick to it. A chorus of boos erupted from the floor at the mention of Hillary Clinton’s name. My note-taking hand froze. Did I actually hear that correctly? Was the DNC booing its own nominee? I wasn’t imagining things. Every time a speaker on the stage said Clinton’s name, the delegate floor belted out a chorus of boos. They also booed her running mate, Tim Kaine.

These were the Sanders people, of course. No one should have expected them to be any happier with Kaine than they were with Clinton. They would have settled for progressive firebrand Elizabeth Warren, but they really wanted Sanders as Clinton’s vice president. The Clinton campaign didn’t consider either. Sanders had already yanked Clinton to the left of her comfort zone. Kaine helped anchor her to the center. Choosing him was a way of saying: enough.

Former Colorado representative Wellington Webb took the stage and tried to smooth things over with the mutinous faction. “Both candidates deserve our cheers,” he said. “Let’s cheer Bernie when he takes the stage.” Everybody cheered, including the Clinton delegates. Then he said, “Let’s cheer our nominee.” Cheers and boos filled the arena, the boos lasting longer.

Diane Russell, who serves in Maine’s House of Representatives, took the stage next. She’s a Sanders supporter who revels in the radical language of Occupy Wall Street. “We are the party of the 99 percent and the working class!” she shouted to muted cheers from the audience. Not everyone seemed comfortable with that narrative. I especially doubted that the Democrats at the Small Business Council meeting I’d attended earlier felt comfortable with it. It’s a story that many on the left like to tell themselves and their voters, but Sanders was correct when he claimed that during the 2008 election season, Barack Obama raised more money from Wall Street than any other presidential candidate in history, including Republicans. Obama raised almost twice as much as his Republican opponent John McCain, a staggering $17.3 million in Wall Street cash, compared with McCain’s relatively paltry $9.7 million. Clinton, likewise, is no standard-bearer for Occupy Wall Street. She still won’t release the transcripts of the private speeches she made to Wall Street executives, almost certainly because she doesn’t want the Sanders wing—or Republicans—to know what she said. This year, the poorer parts of America—the Rust Belt, Appalachia, West Virginia coal country, and most of the rest of America outside the rich coastal enclaves—are pulling for Trump, anyway.

The Sanders wing of the party desperately wants to change that, but it’s not happening in 2016. Russell tried to put a happy face on it, though, by saying, “We will always have a voice in the Clinton administration,” but Sanders delegates in the audience screamed “Nooo!” The Sanders supporters booed Russell every time she mentioned Clinton’s name.

Millions of Americans tune in seriously to politics for the first time in an election year during the conventions of both parties, and the Sanders delegates were throwing sand into the gears. It must have looked and sounded terrible to undecided voters, so Sanders sent a message to his delegate whips. “Our credibility as a movement will be damaged by booing, turning of backs, walking out or other similar displays. . . . I ask you as a personal courtesy to me to not engage in any kind of protest on the floor. It’s of utmost importance you explain this to your delegations.”

It had zero effect. They jeered Elizabeth Warren with cries of “We trusted you!” They did it to Marcia Fudge, too, who took Wasserman Schultz’s place as DNC chair. “Excuse me,” she said over their incessant booing. “I intend to be respectful of you, and I want you to be respectful of me.” They switched gears only slightly when Representative Elijah Cummings from Maryland took the stage. I could hardly hear a word he said over chants of “No TPP” from the floor. The Sanders wing of the party shares Trump’s dim view of international trade and detests the unratified Trans-Pacific Partnership as much as he does. They razzed Cummings because he opposed an amendment by Sanders and Keith Ellison to change the party platform’s ambiguous stance on the subject, which says, in part, that “there are a diversity of views in the party,” which is entirely accurate. (Sanders wanted the DNC platform to oppose the TPP outright.)

The Clinton and Sanders delegates fought each other throughout Monday evening like unhappy family members in a dysfunctional parent-child relationship. New York Times reporters captured some memorable moments. A Sanders floor delegate rose with tape over her mouth and the word “Silenced” printed across it. Another delegate, Nancy Kaplan, said, “This woman has no idea what real oppression looks like. It’s lovely when they cheer for Bernie. I think it’s inappropriate and rude when they boo.” Meanwhile, Clinton delegate Sue Savary from California accurately described the Sanders delegates as “kids.” Sanders delegate Robert Shearer, half her age and without a hint of irony or self-awareness, said, “Ageism sucks. You’re old.”

Sanders himself finally took the stage and went full-tilt after Trump. “We need leadership which brings our people together and makes us stronger,” he said, “not leadership which insults Latinos and Mexicans, insults Muslims and women, African-Americans and veterans, and seeks to divide us up. By these measures, any objective observer will conclude that—based on her ideas and her leadership—Hillary Clinton must become the next president of the United States. The choice is not even close.”

His own delegates booed him.

Sanders seemed bewildered by the forces he had unleashed. He hadn’t just railed against Clinton during the primary campaign. He had told everyone in America that the economy is rigged, that they’re getting screwed by the system, that Clinton is a part of that system, and that what America needs is a socialist revolution. Perhaps for him, this was just rhetoric, but his most ardent supporters and delegates took it seriously. They will continue fighting without him, no matter what happens this year.

On the second day at the Wells Fargo Center, I heard no booing, no jeering, and no catcalls because the booers, the jeerers, and the catcallers walked out. The Sanders delegates left en masse and occupied the press tent outside. Their seats on the convention floor remained empty. It felt as though a boil had been lanced in the arena. The tension was gone. I could hear the speakers without any trouble.

The convention was less interesting, though, without all the drama and hissing. It finally became what it was intended to be from the beginning: a pep rally. There were no panel discussions, debates, or tough questions; nothing was unscripted. Who can stand this? I wondered. Even the party hacks must get bored with it. DNC officials were happy, though. With the Sanders delegates seething outside instead of inside, the Democratic establishment finally got what it desperately wanted—the appearance of unity. Not once on Tuesday did anyone on stage lash out at Sanders or his supporters, and no one in the audience booed Kaine or Clinton. All the kvetching was directed at Trump and the Republicans, along with some appeals to Republicans and right-leaning independents uncomfortable with Trump to vote Democratic this year.

The Sanders delegates eventually returned to their seats and resumed their disruptive behavior. When Vice President Joe Biden said, to a standing ovation, “We have the largest fighting force in the world,” the Sanders contingent chanted, “No more war!” They were drowned out by a much larger crowd chanting “USA! USA!”

The overwhelming majority of Sanders supporters have no memory of Soviet totalitarianism or the Berlin Wall; they know nothing of a world in which the United States was not the world’s only superpower, a world where, if America had slipped, human rights and democratic government might have been eclipsed almost everywhere. The Sanders delegates, when they get older, likely won’t take pride, as Biden does, in America’s military strength. Their lives, and their generational experience of history, are drastically different. And the Democratic Party—and the Republican Party, too—will have to reckon with this.

On Wednesday, July 27, Bernie Sanders resigned from the Democratic Party and returned to his default status as a socialist Independent after spending the primary season as a Democrat-in-name-only, or DINO.

At least two Sanders delegates said that the United States should completely disarm and have no military at all.

His most strident alt-Left supporters aren’t happy. Truthdig columnist Chris Hedges, for instance, who recently signed a contract with Vladimir Putin’s propaganda channel RT (Russia Today), effectively dubbed Sanders a traitor. “Whatever resistance happens will happen without him,” writes Hedges. “Whatever political revolution happens will happen without him. Whatever hope we have for a sustainable future will happen without him. Sanders, who once lifted up the yearnings of millions, has become an impediment to change. He took his 30 pieces of silver and joined with a bankrupt liberal establishment on behalf of a candidate who is a tool of Wall Street, a proponent of endless war and an enemy of the working class.” Many Sanders voters will doubtless hold their noses and vote for Clinton. But those who made it their mission in life to get Sanders the nomination, especially his delegates, are hewing closer to the Hedges line.

I had dinner with six Sanders delegates from my home state of Oregon. They were friendly but suspicious of me, believing that most journalists are in the tank for Clinton. None wanted to be quoted by name, not only because they don’t trust the media but also because they don’t trust the Democratic establishment, which they feared would punish them for speaking their minds. “We’ll lose our credentials if we complain too much to the media,” one woman said. “We were told to just talk about unity.” I don’t know if she was right, but I did notice that the DNC made it easier to remove a delegate’s credentials than a journalist’s. I had a press pass that gave me access to the Convention Center and the Wells Fargo Center for the whole week, but the delegates had to get brand-new passes each morning. Pulling their credentials wouldn’t have been difficult.

“When any of us got up to use the bathroom, paid Hillary shills took our seats,” a woman said. “They want to push us so hard that we won’t come back.” She teared up at one point. I gently tried to steer the conversation toward something else.

“I don’t know how to talk about anything else.”

I asked them to tell me the biggest problem they had with Hillary Clinton and the Democratic establishment, to narrow it down to one or two things. I got a variety of answers.

“Our biggest problem,” a young man said, “is her lack of integrity.” Everyone nodded. They had other complaints, though, that set them far apart from Clinton and the party’s establishment and placed them firmly in the camp of the alt-Left.

“The Democratic Party hasn’t gotten rid of patriotism yet.” This was a complaint.

“Chants of USA, USA were disturbing. I felt like I was in Germany in the 1930s.”

“They brought out the flag and sang the national anthem.”

“You have a problem with the national anthem?” I asked.

“It makes me uncomfortable.”

“Every country in the world has a national anthem,” I said. “It’s perfectly normal.”

“Just because something is normal doesn’t mean it’s a good thing.”

Some surprised me again by agreeing with Trump’s lambasting of NATO. “These entangling alliances are going to get us into World War III.” At least two of these Sanders delegates said that the United States should completely disarm and have no military at all, like Costa Rica.

These kinds of ideas, if they’re ever championed from the stage at a Democratic National Convention in the future, would overturn the long-standing bipartisan foreign-policy consensus and severely strain the alliance holding the West together. Even if isolationism undergirds a new foreign-policy consensus in America, a party espousing these ideas would find it extraordinarily difficult to win a general election. The alt-Left is no more palatable to moderate swing voters than the alt-Right. That, I suspect, is one of the unspoken reasons that the Democratic establishment wanted to muzzle these people, why it wanted to push them so hard that they do not come back, why it wanted Bernie Sanders beaten.

I asked everyone at the table if they intend to quit or to keep fighting inside the party. All said that they would keep fighting. None said that they would vote for Clinton. As far as they’re concerned, she’s a Republican.

How long can these people peacefully coexist in the same political party as the likes of Joe Biden? These young millennial delegates are the rising generation. They preferred Sanders over Clinton by a margin so overwhelming that the word “landslide” doesn’t even begin to describe it. Their collective vote was more like a tectonic shift that forced a new mountain range up out of the plains.

There’s nothing inevitable in politics, but these delegates, if they take over the Democratic Party in the future, will control the platform and the messaging, and their extreme views, combined with their generation’s startling disregard and even contempt for democratic and broadly liberal principles, will scare the daylights out of moderates in the party and could easily trigger an existential crisis. Don’t think it can happen? Nobody saw the rupture of the Republican Party coming. If the Democrats crack up after another election cycle or two, however, we’ll look back to the 2016 primary and the convention that followed, when Bernie Sanders and his young revolutionaries nearly toppled an establishment icon, and say that, yes, this was bound to happen—and sooner rather than later.

Top Photo: A young Democrat protests the nomination of Hillary Clinton at the 2016 Democratic National Convention in Philadelphia. (LI MUZI/XINHUA/GETTY IMAGES)