When you’re a rock band with an Irish lead singer and a knack for blending punk with Celtic music, you’re in big demand for St. Patrick’s Day. That’s certainly the experience of Flogging Molly, a group renowned for getting its Irish up during spirited live shows.

But the group can’t be everywhere on St. Paddy’s. That’s why several years ago, it launched the “Green 17” tour, a 29-city countdown to everyone’s favorite drinking holiday.

“We figured out what we would do is put a tour together to broaden St. Patrick’s Day to your city, no matter what day it was,” said Flogging Molly mandolinist/banjoist Bob Schmidt. “I think it’s one of those holidays that people are happy to celebrate any damn day of the year.”

This year’s tour, which comes to Diamond Ballroom on Tuesday, gives the seven-piece outfit an opportunity to premiere songs from its fifth studio album, “Speed of Darkness,” slated for release May 24.

The title’s allusion to darker themes is no accident. Front man and chief songwriter Dave King wrote the tracks with his bandmates — Schmidt, guitarist Dennis Casey, fiddler Bridget Regan, bassist Nathen Maxwell, accordionist Matt Hensley and drummer George Schwindt — over a four-month stint in Detroit. The beleaguered city, among the hardest-hit by the recession, proved a significant influence.

“I think the global economy and people losing their homes and businesses and all of this was definitely weighing on Dave’s songwriting,” said Schmidt. “That was something he was already writing about and feeling, and I think being at the epicenter of it in America was definitely helpful.”

But Schmidt said the resulting disc is hardly a musical downer. He likens the group’s hard-charging social commentary to the tradition of punk icons such as The Clash and The Jam.

People are happy to celebrate St. Patrick’s Day any damn day of the year.

—Bob Schmidt

“The greatest material of those bands came when the economy was failing in London,” he said. “The music was about the frustration and the failing and betrayal of the working class and this failure of the country to give a hand to people. When you look at London in the late ’70s and early ’80s, it was exactly the same as it is in America now.”

However, Schmidt said he’s certain better times are ahead.

“Everything heals and moves on,” he said. “Detroit was a great place where that was happening. People were taking neighborhoods and turning them into agrarian blocks of farmland in the middle of the city — people re-imagining what the city of Detroit means to them. I really feel that’s going to be the way forward, not clinging to these outdated ways of how you perceive things, and just being open to what needs to be and what it can be.”

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