There’s a clue to the Klezmatics’ longevity hiding in plain sight on the New York City band’s website.

Next to capsule biographies of its six members are their respective autographs, all of which incorporate a caricature of the player and their instrument. It’s a hint, perhaps, that while the klezmer virtuosos have strong personal identities, they share a common sense of humour and strength of purpose.

It’s an idea that certainly amuses singer and accordionist Lorin Sklamberg, a 30-year veteran and founding member of the group. “No one’s ever mentioned that before, so thanks for noticing,” he says, interviewed on the phone from his home in Brooklyn. “Those just kind of developed over time…but it’s not like we consciously sat down and said, ‘Okay, you have to do something that has your signature and your favourite instrument.’ Everyone just saw what everyone else was doing, and it just morphed into that.”

And there’s another clue to this band’s staying power: its willingness to evolve. Today, the Klezmatics are seen as one of the most significant contributors to the worldwide klezmer revival and as a band that’s able to merge historical music with progressive politics. When the group formed, however, its mandate was simple: having fun.

“It was pretty much just people wanting to play tunes, and then wanting to make some extra money by playing parties and such,” Sklamberg recalls. “The idea of making it something more, and it becoming much more personal, was something that came a little bit later.”

Just as the sextet’s sound has diversified, so has its constituency. The Klezmatics still focus on the music of Eastern Europe’s Jewish communities, but two of the group’s main composers, trumpeter Frank London and multi-reed player Matt Darriau, bring avant-jazz fire to the mix, while relatively new addition Lisa Gutkin specialized in Celtic fiddle music before deciding to explore her roots.

Collaborations with poet Allen Ginsberg, the Woody Guthrie estate, the Pilobolus Dance Theater, classical violinist Itzhak Perlman, and Moroccan trance specialists the Master Musicians of Joujouka illustrate the Klezmatics’ adaptability, which is further strengthened by a strongly progressive political bent.

All those elements—a willingness to explore, an openness to collaboration, a strong sense of history, and a passion for social justice—come together on the group’s latest release, Apikorsim. As Sklamberg points out, it’s especially notable for reviving Catalan songwriter Lluís Llach’s antifascist anthem, “L’Estaca”, in translated and retitled form.

“It’s about fighting for your right to exist as a people, as the transmitters of culture through your songs and your language,” he says of the tune the Klezmatics now call “Der Yokh”. “I thought it would make a really great Yiddish song, so we had a friend of ours who’s a Yiddish scholar adapt it for us.…Just last week we performed the song in Spain for the first time, right in the middle of Catalonia, and the audience just went berserk. It was just such a fantastic thing to bring ‘L’Estaca’ back to the place where it was created, and basically say ‘Thank you for giving us the gift of this song.’ ”

The timeliness of the gesture is not lost on the members of the Klezmatics, even though Apikorsim—which takes its title from the Yiddish word for “heretic”—was recorded two years before fascists seized control of their own country’s government.

“We didn’t plan this,” Sklamberg says. “But it turns out that these songs, which are sort of on the continuum of what we’ve been doing for 30 years, have a slightly bigger resonance now then they did when we came up with the repertoire and recorded the CD. So that’s very exciting, too.”