Sheryl Crow’s been working up to this. Shortly before the Iraq invasion, she wore a no war guitar strap onstage at the Grammys. Last year she joined environmentalist Laurie David for a Stop Global Warming college tour and sparred with former Bush adviser Karl Rove during a Washington, D.C., dinner. She’s 46, a single mother who’s survived breast cancer and her breakup with Lance Armstrong. The sun-soaking rock-chick persona that’s served her well since her 1994 debut is getting old. She sure seems to think so.

On her sixth studio album, Crow gets superserious, tackling one heavyweight topic after another. “God Bless This Mess” starts as an off-the-cuff acoustic rumination on family holidays, then balloons into a bitter appraisal of Bush’s post-9/11 march to war. “Shine Over Babylon” is a surrealist diatribe about America’s failed Mideast policies. “Love Is Free” condemns the havoc Bush’s Katrina response wreaked on ordinary lives. And “Diamond Ring” is a primal scream about the Armstrong affair: “Diamond ring/Fucks up everything,” she wails. Apparently he’s her least favorite mistake.

For all its ambitions, Detours aims too low. Crow camouflages her leftist ideas in lighter-than-usual Stones grooves and flat arena beats, as if hoping the red-staters won’t notice she’s gone pink. “Gasoline” offers an apocalyptic vision of rioting farmers and Mini Cooper drivers fighting over dwindling reserves, then cheaps out with a feel-good chorus: “Gasoline will be free/Yeah yeah yeah.” “Out of Our Heads” is an unwelcome Madonna moment that marries sermonizing with disco overload. The party atmosphere feels forced.

Detours works better when it scales back. The title track is an intimate country lilt about feeling bereft and unloved and needing her mom. “Mother, teach me to love with a paper-thin heart,” Crows sings, in a pitch-perfect voice hanging between country ache, soul yearning and pop eloquence. It’s cute, it’s sad, it’s a killer and a beaut—just like Crow, when she remembers to trust her instincts.

Download: “Detours”