On Manifestra, Erin McKeown leaps fearlessly from the personal to the political. The Massachusetts-based singer/songwriter has long shown a knack for combining old-time musical elements with a contemporary lyrical attitude. Manifestra takes these tendencies further with its spiky guitar lines, jittery rhythms, and intriguing arrangement ideas. In tones that range from caressing to challenging, McKeown skewers hypocritical office-seekers (“The Politician”), probes high-level deception (“In God We Trust”), and decries sanctioned violence (“The Jailer”). Of particular note is “Baghdad to the Bayou,” a broadside against corporate greed set to a swampy groove that features lyrics cowritten by political commentator Rachel Maddow. More oblique but no less compelling are tracks like the buoyant “Histories” and the thoughtfully tender “Delight/Divide.” Ryan Montbleau duets on “Instant Classic,” a teasing tune edging into Jason Mraz/Colbie Caillat territory. Those who fondly remember Erin’s early hit “Blackbirds” will enjoy “That’s Just What Happened,” a woozy New Orleans excursion punctuated with a sunny gospel interlude.