Longtime TV writer Straczynski shaped this truth-is-stranger-than-fiction tale of 1920s L.A. into a prestige vehicle. That is no small feat, as the true story took place over years and didn’t reach a definitive conclusion. Christine Collins’ struggle against the LAPD’s near-dictatorial powers hits a nerve with a nation pondering the future of Guantanamo and secret prisons. Thoughtful, somewhat upbeat ending to a downbeat tale owes much to Straczynski.WHY IT’LL WIN: Earnest drama with family themes and liberal overtones is in Oscar’s sweet spot. MAYBE NOT: Its adherence to real events keeps it from offering a tidy resolution.