It’s a curious thing that in the movie culture of the last 50 years, you can count on one hand (or maybe one middle finger) the good dramas that have been made about the political counterculture of the 1960s. The turbulence of that era has never stopped casting a shadow over our own. Yet there’s something about it that resists being captured with any real onscreen authenticity. When you gather up a bunch of actors and dress them like hippies and have them carry protest signs, it tends to look like what it is: a staged insurrection. And the ’60s were such an amped orgy of media signifiers — the flower-power fashion, the groovys and hey, mans, the rock psychedelia, the jabbering on about revolution — that the era, viewed in hindsight, has a way of devolving into a compost heap of clichés.