A specter was haunting the Inner Harbor. Gathered at the Hilton Baltimore last weekend were the members of the Congressional Progressive Caucus. For decades, the CPC has been a well-meaning but largely ineffectual expression of the left wing of the House Democratic caucus.

But something has changed, and this year their strategy session was joined by delegates from openly left-wing parties around Europe, all members of parliaments in their respective countries. Among them were a few characters who don’t usually frequent Democratic Party functions: socialists.

One was British Labour Party Member of Parliament Diane Abbott, who could — pending the result of the next U.K. general election — become one of her country’s top-ranking officials. Abbott was the first black woman elected to Parliament and a lifelong organizer. Like the Labour Party leader and potential future prime minister, Jeremy Corbyn, she’s also a socialist, a word she didn’t shy away from in her address to the CPC gathering. The label had landed her, Corbyn and other Labour MPs squarely on the back bench for most of their long careers in government, with socialist policies laughed off almost as quickly as they were voiced, under conservative and Labour governments alike.

In the last few years, something changed. Corbyn’s run for Labour leadership brought tens of thousands of people — many of them young and anxious about the direction of global capitalism — into the party’s fold, excited to not just vote for but actively campaign in support of a man who’s called Karl Marx a “great economist.” In a snap general election this summer, Labour outperformed even the most optimistic of expectations.

They didn’t win, but did displace Tory Prime Minister Theresa May’s majority and pick up 30-odd seats in Parliament. Abbott and others credit their surprise success in large part to the party’s manifesto, prematurely leaked to a conservative press that thought its unveiling could put the nail in Labour’s coffin. Tory-leaning tabloids warned of the party’s plans to “nationalize energy, rail, and mail” and “scrap tuition fees.” It turns out that’s exactly what many voters wanted to hear.

“I have contested eight general elections,” Abbott told me on Saturday. “I have never had people come up to me in the street and say, ‘I really like your manifesto.’” She explained that the dreaded S-word and proposals therein hold a particular resonance for young people: “They know that the current system isn’t working for them. It’s hard to have much commitment to capitalism if you don’t have any capital, and no prospects of getting any.”

It’s amid today’s socialist resurgence that audiences will watch director Raoul Peck’s latest film, “The Young Karl Marx,” now screening on limited release in the U.S. and available on demand. “I never thought someone would finance a film like this,” he confessed that he had doubts about the viability of his new release.

Peck has a storied career, including an Oscar nod for last year’s “I Am Not Your Negro” about James Baldwin, a string of critically acclaimed films and a stint as Haiti’s minister of culture. If there was ever a time within it to make an adoring biopic about one of history’s most controversial and influential thinkers, it’s 2018. And that’s because the film is not, as Peck has said, about history, but about the present — and made specifically for today’s young people.

Indeed, the specter haunting the U.K. is here in the U.S. as well. Socialist Bernie Sanders — a co-founder of the progressive caucus, as it happens — is holding strong as the country’s most popular politician, and membership in the Democratic Socialists of America continues to tick upward after a post-election explosion. Democratic socialists are even winning elections, including in places like Virginia and Montana. Millennials in particular are flocking to socialism, unencumbered by the hang-ups that plagued their parents’ generation. For those who grew up in the wake of the Cold War, socialism means “Medicare for All” and more humane and democratic workplaces, not gulags and Five-Year Plans. Capitalism, for those who graduated college in the mid-2000s onward, meant a searing financial crisis, unemployment and underemployment, itinerant labor through endless internships, and insurmountable student debt.

Connected to all this popular outrage at the system bequeathed by baby boomers was a series of uprisings — Occupy Wall Street, Black Lives Matter, Dreamers, and more. Millennials have been at the forefront of each. And while none of these movements articulated their politics as uniformly socialist — some underpinned by an affinity for anarchism that Marx would have recoiled from — they all sent out rallying cries that have helped move people in a radical direction: We’re getting screwed, and we’re pretty sure capitalism has something to do with it.

That many are now coming to socialism through activism, rather than theory, is probably more of a blessing than a curse, and might finally allow the socialist left to shed its image as the province of crotchety, dogmatic newspaper-sellers raring to pick fights about the political leanings of Rosa Luxemburg’s murderers. Peck’s film touches on the endless amount of time that Marx (August Diehl) spent in rhetorical combat — through letters, pamphlets, books, and backroom maneuvering at conventions — even before the advent of Twitter (which, had it been available to him, may have prevented even the completion of a single volume of “Capital”).

What Peck’s film does well, then, is provide this new generation of socialists — those who may never have cracked open the “Grundrisse” — with an accessible entrée into the ideas upon which today’s socialism is built.

There aren’t many spoilers to give about a theory-laden movie depicting a long-dead man whose every word has been scrutinized across the globe for well over a century. That said, this review will be relatively free of them. To summarize: “The Young Karl Marx” tracks Marx’s career from the turbulent years of 1843 through 1848, spanning the philosopher-cum-economist’s exile from Germany at age 26 through the publication of the “Communist Manifesto,” a multi-lingual reading of which the film concludes with. Its most important plot point is his meeting a bright-eyed, similarly young Friedrich Engels (Stefan Konarske) in France, and the core story traces the development of their friendship and intellectual partnership. While it flirts with the conventions of period dramas, “The Young Marx” is, above all, an ideological coming-of-age story for a generation doing exactly that.

In this, “The Young Karl Marx” engages in its own kind historical materialism, to use a loose sense of the term. Marx’s work — and socialist and academic interpretations of it, in particular — can feel hallowed, like infallible sacred texts sent down from on high. True to life, the Marx we see is no saint: He drinks too much, has sex, procrastinates, burns bridges, and is a sometimes absent husband and father. What Peck offers is a human (albeit unmistakably flattering) portrait of Marx and Engels, men who were each shaped deeply by their circumstances — the particular moment in history that they happened to find themselves, the idiosyncrasies of the movements they aligned themselves with, the friends and partners with whom they collaborated, maybe even the number of drinks they had on a given night.

Peck, for instance, posits a likely apocryphal origin story for Marx’s “Theses on Feuerbach”: a drunken night out with Engels. Stumbling home, Marx confesses to his new friend that their many rounds of drinks have led him to an epiphany, going on to paraphrase one of that work’s more memorable lines: “The philosophers have only interpreted the world, in various ways; the point, however, is to change it.”

