Only the most blinkered curmudgeon would oppose all reunions, but let's be real: Some regroupings make more artistic sense than others... and some do serious damage to legacies. Was anyone clamoring for Gang of Four's Content or Pixies' Indie Cindy? Will fans develop lifelong relationships with the comeback albums the way they did to Entertainment! or Surfer Rosa? Doubtful.

Which brings us to the Pop Group, who weren't popular but thought they should have been; the name may have been ironic, but it wasn't intended to be sarcastic. These furious vigilantes from Bristol, England, cut two classics of post-punk agitprop—1979's Y and 1980's For How Much Longer Do We Tolerate Mass Murder?—plus another strong comp from 1980 called We Are Time. On these recordings, Mark Stewart's bilious vocals boiled over savage funk, dub, Ornette Coleman–esque jazz, and no-wave rock. Few bands had so cohesively linked bluntly progressive activist lyrics to revolutionary sounds. Their brutally uplifting "Where There's a Will"—James Brownian funk in steel-toed boots channeled through tense, white Anglo bodies—should be a standard at all social-justice rallies. It made perfect sense that the Pop Group collaborated with proto-rappers the Last Poets on "One Out of Many" in 1980, years before hiphop came into its own as an art form. Both artists combined radical, inflammatory expression with an artistic sensibility, combating sociopolitical madness with a more inspired, cleverer variant of their own. The works of both groups stand as cultural Pyrrhic victories that still ignite passions decades later.

The Pop Group fragmented in 1981 due to creative disagreements and legal problems, but they returned to the fray in 2010 to play sporadic live dates and cut some new songs. Five years later, they're finally touring North America for the first time in support of their new opus, Citizen Zombie. Though Stewart, guitarist Gareth Sager, bassist Dan Catsis (replacing Simon Underwood), and drummer Bruce Smith haven't budged an inch from their leftist beliefs, it would be folly to expect the old Thatcher-era nuclear firepower from gents in their 50s. Still, the songs on Citizen Zombie are mostly solid. They might have had a better chance if producer Paul Epworth—who's worked with Paul McCartney, Lana Del Rey, Azealia Banks, and others—hadn't sugarcoated the Pop Group's caustic rhythmic impact. It's odd to hear a relatively slick love song like "Nowhere Girl" with breezy backing vocals and bubbly synth sheen by these cranky instigators. Here and in other scattered moments, the Pop Group sound determined to live up to their name. Citizen Zombie strains for relevance and sometimes achieves it ("Shadow Child" especially retains the band's stealthy urgency), but the Pop Group's guerrilla hardness has gone a bit soft, its rhythmic attack a bit clunky.

But a record is only one facet of a band's identity. The Pop Group of 2015 is pugnacious and clearly determined to matter in a way that we used to expect from all rock bands. The question of their relevancy was buoyed further when St. Vincent covered their stormy, existential 1979 debut single "She Is Beyond Good and Evil" on Late Night with Jimmy Fallon in 2012. Seeing as the Pop Group received scant US press during their first go-round, it seemed worthwhile to interview these opinionated provocateurs, to see what the ensuing decades had done to their outlook. In Japan when our e-mail interview transpired, Pop Group frontman Stewart fielded the questions, seemingly under many pressing demands; his answers were curt and appeared to be torn from the notebook of a young anarchist. When asked what made him think the world needed the second coming of the Pop Group, he replied, "A mass of tangled hope and unfinished business, and the real need for radical social change."

Stewart's righteous indignation toward a world rife with injustice hasn't diminished, but his views don't appear to have evolved into more nuanced and insightful condemnations. He always had something of the wild-eyed street-corner preacher about him, but his paranoia didn't prevent him from making some valid points. Reading verbatim from Amnesty International's catalog of abuse on the song "Amnesty Report," Stewart flicked a switch about state-sanctioned brutality in a lot of impressionable teenagers' minds. Whether he and his mates can effect the "radical social change" he mentions above in a commodified world full of people hypnotized by social media and smartphones remains unlikely, as it's never been harder for belligerent middle-aged guys with clangorous guitars to change minds and win hearts on a mass scale. But at least there's some vigorous physical exercise and overdue financial recompense in the attempt.

An early Pop Group song title, "Genius or Lunatic," could apply to Stewart. For a couple of years during the Pop Group's fertile peak when I first heard their music as a teen, he really came across as a catalyst for change, ranting about "consumer fascism," asking "who guards the guards/who polices the police," and commanding us to "feed the hungry." Thirty-five years later, a lot of what Stewart said still rings true, but his current spiel about "the zombification of society" and "choking dissent from birth" oversimplifies things. Does Stewart think that we're still, in the words of the band's most galvanizing song, all prostitutes? Of fucking course. "The planet is spinning out of control as the power elites use proxies and false flags in resource wars. It's insane." Quite. Nevertheless, it'll be a thrill to hear old faves like "Thief of Fire" and "We Are Time" in the (sagging) flesh.