While the politics of the British singer-songwriter Billy Bragg have always remained consistently to the left, his music has veered from tight brashness to messy looseness — especially when he’s backed by a band. The bristling, reedy Mr. Bragg that emerged in England in the early 1980s backed himself only with his propulsive, provocative electric guitar, a busking punk approach that complemented his personal-is-political songwriting. But his relationships with backing bands have veered from the promising (1986’s “Talking With the Taxman About Poetry”) to the outright clumsy (1991’s “Don’t Try This at Home”) to the borderline sublime, namely the two “Mermaid Avenue” albums, on which he collaborated with American alt-country heroes Wilco. Mr. Bragg has never enjoyed such richness with his own band, the Blokes, which he formed in 1999, and his last album, 2003’s “England, Half English,” sounded like a mature solo artist trying to find room for all these different ideas and guests.

Mr. Bragg may well have nailed the formula with his new album, “Mr. Love and Justice” (Anti- Records), out today. His second album with the Blokes settles into an inviting groove that fuses folk-rock and old soul, and expresses political ideas more through the intimacy of personal observations than with rhetoric. While nowhere near as fascinating as the “Mermaid Avenue” albums, or as immediately rousing as his early work, “Mr. Love and Justice” does offer a rosy, vital peek at what Mr. Bragg still has to offer his fans after 25 years of agitprop pop.

It doesn’t all start off roses, though. The lead single and opening track, “I Keep Faith,” is a lugubrious ditty elevated only by a reverential organ line from Ian McLagan (who provided the same sort of dignified mood to the Faces in the 1970s) and by Robert Wyatt’s ethereal backing vocals on the chorus. It’s not a bad song; just overwhelmingly ordinary.

On the few songs on which Mr. Bragg and the Blokes stick to a similarly conventional approach, “Mr. Love and Justice” feels as uneven and listless as some of his previous scattershot full-band albums. Fortunately, far more tracks offer a more freewheeling attitude. “I Almost Killed You” skips along almost like a traditional folk sing-along, urged forward by a kinetic rustle of hand-claps and a whimsical violin, with an electric guitar piping in momentarily and a bowed bass adding a grave bottom to the chorus. The rumbling “The Beach Is Free” sounds like the Band in its “Stage Fright” era falling gloriously apart after spending about a week in a Northern England pub, its central ramshackle groove constantly threatening to veer out of control but never quite losing its cool. “O Freedom” whips along at a brisk clip on the almost funky collision of guitars and mandolins. And the sparsest of guitar textures and percussion color the melancholy of “If You Ever Leave,” a pretty love song from the perennially romantic Mr. Bragg.

But the highlights on “Mr. Love and Justice” truly occur when the Blokes offer their rich take on American soul music. “Sing Their Souls Back Home” melds stirring bits of church organ and gospel vocals to a swaying country tune. It’s a vibrant mood echoed on the even more elemental title track, where Mr. Bragg’s odd, sandpaper rasp feels perfectly at home inside a talking-blues preacher setting. His voice has always been his most beguiling weapon. Nothing brings an engaging humanity and vulnerability to his ideals and love songs quite like a voice that has never been able to hit a proper note. It sounds almost as if Mr. Bragg sings not because he can, but because he has something he must purge from his head and heart.

That lack of polish in Mr. Bragg’s voice was what lent his early, splintered love songs such an electric jolt, like a man trying to figure out how to navigate the everyday world, where the drudgery of the work day can be turned around by a woman’s smile. That young man is now a married father living in Dorset rather than London, but Mr. Bragg’s beliefs never mellowed. On the title track on “Mr. Love and Justice,” he comes out on the side of fighting the fight, regardless of how desperate it looks. Mr. Bragg confesses that, after all the years and albums, he still faces many of the problems he always has, asking, “Is there any love or justice in the world today?”

He doesn’t wait for an answer, instead deciding, “If only for my sake, I’ve got to see this thing through / I’ve just got to find out if I was right or I was wrong.” Self-doubt is a standard emotion from Mr. Bragg, but it still seems refreshingly candid during the political season, when right and wrong are often regarded as impervious to debate. Mr. Bragg offers a riveting reminder that ideas — political or otherwise — are only as decent as the people who make them.