The Band Perry

The Band Perry performs at the Toyota Oakdale Theatre in Wallingford on May 1. (David McClister, Splash Publicity / January 14, 2013)

Country music is the most popular radio genre in the country, and Taylor Swift is the biggest pop star in the world. Why?

There's no shortage of voices — pundits, critics and industry execs — chiming in on what's driving the ten-gallon takeover: the allure of Nashville, and the prime-time placement of shows like "Nashville"; the lock-step programming of country-radio stations nationwide; the rise of events like Austin's iHeartRadio Country Festival; shifting demographics, and so on.

"It's always been the genre that tells stories, life stories," said Kimberly Perry, who performs and records with brothers Neil and Reid as the Band Perry. "That's something that everybody holds on to."

Maybe you've heard of them. The Band Perry's self-titled 2010 debut album sold over a million and a half units, largely on the strength of the single "If I Die Young," which alone sold nearly 5 million. They've had other stratosphere-reaching singles since then, and another album, "Pioneer," which came out last year. But mostly the later accomplishments, any one of which would be life-changing for an unproven act, feel like aftershocks — or maybe victory laps after a NASCAR triumph — of that one seismic single.

Perry spoke to CTNow by phone while the group was en route from Bakersfield, Calif. to Flagstaff, Ariz.

"The country umbrella is a really, really wide one," she said. "Folk country, rock country, pop country: It's almost like country music is one of the last rock and roll frontiers. It gives artists a lot of flexibility, and that's what we're looking for. Our fans are looking for that too."

Nobody can rightly accuse the Perrys of being inflexible; their sound, although peppered by some of the cliched country tics — acoustic instruments, banjos, mandolins, fiddles, pedal steel guitars, dropped Gs and so on — is a thoroughly contemporary one, and it's kept up with the times. While "Walk Me Down the Middle," from the first album, introduces schmaltz-style strings, the kind you might have heard on a late-'60s Glen Campbell countrypolitan number, very little on "Pioneer" shares that texture. On "Better Dig Two," the first track on "Pioneer," which starts out with gently plucked banjo strings, Kim abandons the squeaky-clean-ness, held over from their early days, in favor of darker thoughts: "It won't be whiskey, won't be meth / It'll be your name on my last breath / If divorce or death ever do us part / The coroner will call it a broken heart."

Kim's vitriol spills over on "DONE," co-written by Neil and Reid (along with John Davidson and Jacob Bryant): "You're one bridge I'd like to burn / Bottle up the ashes, smash the urn," to a bad boy who "crossed the line too many times / I'm gonna put you in your place / You play with dynamite, don't be surprised / When I blow up in your face." Even "If I Die Young," the blockbuster from a few years ago, betrays some considerable moroseness, especially during the chorus, set to a lilting melody, which is repeated no fewer than three times before the song ends: "If I die young bury me in satin / Lay me down on a bed of roses / Sink me in the river at dawn / Send me away with the words of a love song," to which Kim adds, "The sharp knife of a short life / well, I've had enough time." Apparently, there are at least 4.5 million listeners out there who can relate.

Now many months into the We Are Pioneers Tour, the Band Perry have acted as country-music ambassadors to Europe (where they spent a month) and later in Canada (another month). "We planted the country banner overseas," Kim said, "in keeping with our pioneer spirit."

"Paris was a dream come true," Kim said. "No matter where we went, the whole world was ready for country music... There's no traditional country radio over there [in Europe], but I think YouTube has made the world a tiny place." They'll perform at the Toyota Oakdale Theatre in Wallingford on Thursday, May 1, and later this summer, they'll join Blake Shelton's Ten Times Crazier Tour.

In Europe, Kim said, the Perrys spent their nights performing and their days being tourists, frequenting Parisian bakeries and visiting the former site of the Berlin Wall. Being with brothers Neil and Reid, she said, has made the trappings of success easier to navigate. "We've had each other's best interests in mind," Perry said. "It's been a huge support throughout the 15 years we've been doing this… We know that we share the same focus on our workmanship." Later this year, the Band Perry will start focusing on their next batch of recordings.

"Writing for albums has always been our focus," Kim said. "We tell our own stories the best… It's our therapy, our way of communicating, our way of processing the world. It's one part therapy and two parts recess... We always like to push our own boundaries. The greatest spirit of country music is that it's 100 percent authentic."

Editor's note: This story has been updated to correct the title of the album "Pioneer."