At his most effective, British director Ken Loach (Riff-Raff, My Name Is Joe) couches strong leftist sentiments in warm, effortlessly naturalistic melodramas with vivid characters, offhand humor, and an uncanny ear for dialogue. A social realist with a special attunement to class issues, Loach needs this human dimension to validate his point of view; otherwise, the screen begins to look like a giant placard. His didactic tendencies are laid bare in Bread And Roses, an awkward and disappointing treatment of a janitors' strike in a Los Angeles office building. The first film Loach made in America during his 30-year career, Roses takes an outsider's look at the gross inequalities of the richest country in the world, where undocumented immigrants are obliged to feast on (and vacuum up) capitalist crumbs. After she's smuggled across the Mexican border by a pair of shady mercenaries, Pilar Padilla joins older sister Elpidia Carillo and her family in an overcrowded home on the edge of downtown. Lacking legal papers, Padilla is limited to low-wage hourly jobs, but she perseveres and finds work alongside her sister as a night janitor in a non-union servicing company. Minus the requisite kickback of one month's salary she gives to her tyrannical boss (George Lopez) for offering her the position, Padilla and her coworkers labor for $5.75 an hour without health insurance, job security, or other benefits. Her idealism leads her to embrace the efforts of a labor organizerplayed with sensitivity and charm by the always-compelling Adrien Brodywho convinces her group to unionize for a fair wage. For Latino illegals living paycheck-to-paycheck, the risks are as high as their leverage is low. Loach skillfully reveals the strategies and pressures from within and without, as the strikers stare down arbitrary firings and scab replacements from management, and suffer the blowback from understandably skittish employees who capitulate to keep their jobs. But remove the speeches, diagrams, and instructional-video footage, and there's not much movie left. As usual, Loach gets affecting performances from his actors, but the characters and relationships are so perfunctorily developed that they're little more than mouthpieces for a feature-length editorial. Bread And Roses lectures knowingly on immigration and labor problems in America, but the reason Loach is such a vital and distinguished filmmaker is that he rarely needs to lecture at all.