Whether he's wailing passionate lyrics at an Irish pub or railing against tax hikes at a Baltimore City Council meeting, Martin O'Malley is always onstage. And always on a crusade.

Mick O'Shea's saloon, North Charles Street, Friday night. The Guinness is flowing, thick and black as tar. The college students at the bar are working hard on their buzz, and the older people at the tables are picking at their salads and gazing wistfully at the kids, perhaps remembering a time when they, too, could do Absolut shooters without ending up on the couch for the next two days.

On the cramped stage, the Irish band O'Malley's March is playing a gentle ballad full of exuberance, hope and longing for the auld sod.

Well, maybe not:

You're a bum, you're a punk

You're an old slut on junk.

Lying there in the drip,

Nearly dead in the bed.

This is being delivered by lead singer Martin O'Malley. This would be the same Martin O'Malley who sits on the Baltimore City Council with all the restraint of an ax splintering through a door. Given that he's just come here from his day job, he must feel as if he's entered a parallel universe.

As he bites off each lyric, the crowd sings along with gusto to this cover of Shane MacGowan's "Fairy Tale of New York."

MacGowan was the brilliant lead singer of the Irish punk band the Pogues until they kicked him out for being an "irresponsible drunk" -- apparently to differentiate him from the responsible drunks who still consider it bad form to pass out on stage.

Moments later, O'Malley's March begins a listless version of "Black Velvet Band," a tune every Irish band is practically required by law to do. The first four lines feel as musty as the doilies at your granny's house:

And her eyes, they shone like the diamonds

You'd swear she was queen of the land.

And her hair hung over her sho-o-o-ulders

Tied up with a black velvet band.

Gradually O'Malley's voice trails off, as if he's overcome with ennui. The music stops. Then, in possibly the worst Elvis imitation ever heard, he mutters: "That don't do nothin' for me."

Whereupon the band -- bass guitarist Bob Baum, drummer Jamie Wilson, piper Paul Levin, trombonist Jared Denhard and O'Malley on acoustic guitar -- suddenly kicks into some sort of driving, Celtic-boogie version of the same song that soon has the joint rocking out big-time.

In many ways, the two songs represent the essence of O'Malley's March and Martin O'Malley, the city councilman from northeast Baltimore who, on this chilly spring evening, is wearing jeans, boots and a black sleeveless T-shirt and looks more like a clean-cut Springsteen than someone you'd call about a pothole.

When people call O'Malley a politician, spitting the word at him like an obscenity, he replies: "I'm not a politician, I'm a reformer."

And here at Mick O'Shea's, O'Malley is engaged in one of his favorite reformation projects: putting a different face on traditional Irish music.

"What we're trying to do is make Irish music accessible without hurting its integrity," is how he explains it. "The fun part is, yeah, it's traditional [Irish] music if you did it without the drums and the electric bass going on beneath it. But then some people, especially younger people would say: 'OK, we've heard this before. Now let's get the hell out of here.' "

O'Malley admits that too much of traditional Irish music sounds "like taking a cat and beating it against the wall."

"We want to keep telling the stories, keep telling the history, keep the music alive," he says. "[But] make it accessible to a wide range of audiences."

To that end, O'Malley's March plays music difficult to categorize, although O'Malley grudgingly defines it as "Celtic folk rock."

It's not the electric heresy of the Pogues or the dark, pulsating edginess of Black 47. But it's not the traditional jigs and reels of the Chieftains or the lilting ballads of the Clancy Brothers or Christy Moore, either.

And it's damn sure not the music of your average City Council member. Because your average City Council member does not unwind from a 14-hour day by slapping Sinead O'Connor's "The Famine" on the CD player and grooving along to her haunting rap of British cruelty during the Irish potato famine of the mid-1840s:

You see, Irish people were only allowed to eat potatoes

All the other food -- meat, fish, vegetables

Were shipped from the country under armed guard

To England, while the Irish people starved.

Reformers are often given to grand gestures that signal their intentions. Martin Luther posted the Ninety-Five Theses on the door of the Wittenberg Castle Church. Gandhi led hundreds of followers on a 200-mile march to the sea to protest the Salt Acts.

For O'Malley's March, a bar band that's been together for four years, their grand gesture was this: Each man reached hard into his pocket and came up with $6,000 to go into the studio and record their first CD.

The result was "Celtic Fury," released this spring to some local critical acclaim and encouraging sales. It features an eclectic mix of traditional songs given a contemporary feel, plus three original songs written by O'Malley and a slow melody featuring the Uilleann pipes written by Paul Levin.