Several months ago the Internet was abuzz with news that the upcoming Ted Leo album, his fourth, had leaked. That fact in and of itself was nothing special: These days advance downloading is to be expected with any high-profile album not afforded Fort Knox-style security. The novelty in this case is that Ted Leo is hardly a household name, let alone a high-profile downloading target. He is, however, someone who provokes a fervor in his fans disproportionate to his cult popularity. Sit through one of his albums or stand through one of his shows, though, and it all makes sense.

Ted Leo is part of a proud tradition of working-class chroniclers and malcontents, as rooted (loosely) in the protest folk of Woody Guthrie as he is in such ardent late-'70s, early-'80s populists and aggrieved polemicists as Billy Bragg, the Jam, the Clash, Stiff Little Fingers and Bruce Springsteen (the latter more in theory than in practice; Leo's a bit of an Anglophile). But over his last couple of albums, Leo has carved out his own niche, falling somewhere between punk and pop but infused with the poetry of the street.

Leo has stated that his goal with this album was more economical songwriting, and he seems to have achieved it by embracing his latent literary aspirations. "Shake the Sheets" begins with a line that could be the start of a great novel: "As I was walking through a life one morning, the sun was out, the air was warm, but, oh, I was cold." Considering the political dissatisfaction on display throughout last year's excellent "Hearts of Oak," there's no surprise Leo should still feel out of sorts. This is a man who took a job as a dockworker after Sept. 11, 2001, to reconnect with his adopted city of New York, but who still feels helpless and frustrated watching the world spin out of control around him.

"Shake the Sheets" is Leo's third near-masterpiece since the summer of 2001, a sign that his prolific writing stems from a passion both real and overflowing. But that much is clear as the album immediately latches you in for a powerful, hook-filled and, yes, economical 40 minutes. Eagle ears hunting for more politics will easily find plenty. In "The One Who Got Us Out," Leo states, "I'm worried for our tired country," and in "Counting Down the Hours," he references "a story of detainees who were barely kept alive." But Leo delivers these ringers without a hint of preachiness. Instead, his singing reflects a sad mix of resignation and indignation. Is this what we've come to? Am I powerless to stop it? When does talk turn to violence?

Leo's saving grace, what supports his vitriolic take on current events, is his remarkable songcraft and the constant possibility of redemption. With the Pharmacists, the redoubtably vise-tight rhythm section, aiding him, Leo flits from anthemic punk to reggae to folk to Celtic balladry and Thin Lizzy boogie, often over the course of a single song. The cathartic, galvanizing drive of "Little Dawn" offers plenty of optimism, enough to counterbalance Leo's earnest, introspective gloom. However, even he understands the power of hope. "Stretch out your legs and dance with me all night," he demands, whispering "it's all right" over and over again until the mantra makes it feel so, even if the news still tells a different story.

Ted Leo, center, and the Pharmacists (Dave Lerner, left, and Chris Wilson): Powerfully spare and politically potent on "Shake the Sheets."