Before they announced to a London audience in 2003 that they were ashamed President Bush hailed from their home state of Texas, before they bore the brunt of conservative backlash that ostracized them from country music, before anyone ever told them to “shut up and sing,” the Dixie Chicks were controversial. But that ugly dust-up tends to overshadow almost every other aspect of their storied career, including the story of “Goodbye Earl.” A deep cut on their fifth and maybe best album, 1999’s Fly, it tells the story of a battered housewife named Wanda who, along with her best friend Mary Anne, exacts revenge on her abusive husband, poisoning his black-eyed peas for all the black eyes he gave her.

Rather than grim and melodramatic like Garth Brooks’ “Thunder Rolls” a decade before, the Dixie Chicks’ song is upbeat, catchy, sarcastic, and hilarious. Partly that’s thanks to Dennis Linde, the veteran songwriter who earned a spot in heaven for penning Elvis Presley’s late-career hit “Burning Love.” He originally wrote “Goodbye Earl” for his band Sons of the Desert, basing Earl on a leering character from an earlier song and injecting a sordid humor into the storyline. But mostly it’s due to the Dixie Chicks themselves, who turn that first chorus into one of country’s great punchlines and literally taunt Earl’s corpse as it rots in the trunk of their car. “Ain’t it dark wrapped up in that tarp, Earl?” They have a blast stretching out that urrrr until it nearly snaps in half.

“Goodbye Earl” is awesome in so many ways, not least for the way it subverts country music storytelling. In fact, the song rewrites several decades’ worth of murder ballads, those sad, gruesome tales of the many ways men kill women. Here, it’s a woman killing a man. Even more radical than that is the fact that Wanda and Mary Anne get away with it. Rather than waste away in a jail cell (like the killer in “Knoxville Girl”) or live with crushing guilt (like the murderer in “Banks of the Ohio”), they hide the body, fool the cops, and buy “some land and a roadside stand out on Highway 109. They sell Tennessee ham and strawberry jam, and they don’t lose any sleep at night.”

As great as it is, the Dixie Chicks never intended “Goodbye Earl” to be a single, but after they played it at Lilith Fair and on the Grammys, enough of their fans called in enough requests to enough radio stations to make it a grassroots smash. Almost immediately it raised the hackles of country radio programmers and some listeners, and very quickly 20 of the 149 country stations tracked by trade magazine Radio & Records banned it for its subject matter as well as for what they perceived as its glib tone. Some stations paired the song with a PSA for domestic abuse, while one in San Jose held an on-air town hall to discuss the song and the issues it raised. Response was overwhelmingly positive, and “Goodbye Earl” stayed in rotation. It looked like a win for the most popular group in country music: Fly sold more than 10 million copies, and the band took a brief hiatus before following it up in 2002 with the excellent Home. Still, “Goodbye Earl” set them up for the fall they would take four years later.

Coming at the tail end of the 1990s — a decade that saw country music achieve its greatest crossover success, when Garth Brooks and Shania Twain outsold Nirvana and Pearl Jam — Fly synthesizes a popular aesthetic arguably better than any other act of the era, yet remains idiosyncratic enough to retain its personality and twang. Martie Seidel (now Maguire) and Emily Robison (now Strayer) were already exceptional instrumentalists with strong chops and a sharp command of various genres, having cut their teeth on the highly competitive bluegrass circuit in the early 1990s. That comes through on album opener “Ready To Run,” with its flourishes of Celtic pennywhistle and fiddle heightening the urgency of a woman who’s doing her best not to get trapped by prescriptive gender roles. From there the trio marry country twang and pop sheen to gospel hijinks (“Sin Wagon”), torch balladry (“Cowboy Take Me Away”), and rowdy honktytonk (“Hello Mr. Heartache”). It’s an album that never settles down, never runs out of ideas.

Even better than the playing is the singing. The women’s voices all bounce off each other rambunctiously, with Seidel and Robison toggling between lead and supporting harmonies. Part of what makes “If I Fall You’re Going Down With Me” so catchy is the way their voices cascade downward behind Natalie Maines’ lead, essentially enacting the sentiment of the title and giving Fly one of its surest and most unexpected hooks.

And Maines sings to be heard, with a voice that is forceful, sharply expressive, able to convey certain emotions that had been elbowed out of country music during the era of hat acts. On “Goodbye Earl” and “Sin Wagon,” she takes a cue from Roger Daltrey belting “Baba O’Riley” and starts the song at 11, then finds her 12 and 13. There’s a lot of cowgirl in her delivery, but also a lot of punk, which means she can add a vivid sensuality to “Cowboy Take Me Away” but also make murder and “mattress dancin'” (her words) sound like a great night out. In fact, her vocals may be part of what fuels so many of the band’s detractors: Maines is defiant and unapologetic about indulging in a little sin on a Saturday night and doesn’t bother to atone for it on Sunday morning.

Because of long-held attitudes about the plasticity of country pop in the 1990s, it’s difficult to get a bead on this particular album’s legacy in 2019. The Dixie Chicks paved the way for a small wave of country trios in the late 1990s, most notably SHeDAISY, but none had even a fraction of their success. And certainly “Goodbye Earl” inspired similar murder ballads by women artists, including Miranda Lambert’s “Gunpowder & Lead” and Carrie Underwood’s “Church Bells.” Even today they remain a highly influential act, if only for the way they navigated the treacherous crossover waters. It’s no surprise that they harmonize with Taylor Swift on her new album Lover, as she is their spiritual and musical progeny, someone who has learned many lessons from them about how to make great country and great pop and about how to navigate the Nashville straits, for better or for worse.

Even so, they remain a cautionary tale, a story told by label execs to keep young artists from speaking out. “I came from country music,” Swift recently told the Guardian. “The number one thing they absolutely drill into you as a country artist, and you can ask any other country artist this, is ‘Don’t be like the Dixie Chicks! I watched country music snuff that candle out. The most amazing group we had, just because they talked about politics.” On the other hand, the Dixie Chicks helped Swift grow more comfortable speaking about politics, in particular when she called out the White House at the VMAs last week, comfortable that she would not be excommunicated from the industry.

While it’s difficult to narrow that down to the effect of one album, Fly does seem to be emerging as their defining artistic statement, one whose sentiments and attitudes sound as urgent in 2019 as they did in 1999. Just last year Katie Alice Greer, who fronts the DC punk group Priests, covered Fly song for song, taking these songs out of the world of country into something a little stranger, a little murkier. “I decided it would be a fun way to get out of my creative comfort zone, learn about harmonies, practice some recording techniques,” she explained. “I am a huge Dixie Chicks fan and have been listening to this album since I was a kid.” Her covers underscore the vitality of the Dixie Chicks’ originals, how they might speak to the experiences of women of various generations.

Freedom is the ultimate theme of the record, one that remains surprisingly timely 20 years later. Whether they’re running away from a wedding or riding to heaven on a sin wagon, Maines, Maguire, and Robison bristle against any attempt to fence them in or narrow them down. That makes the old ugly adage “shut up and sing” sound weirdly empowering: Their songs remain the most radical thing about the Dixie Chicks.