Ellen Kuras and Thavisouk Phrasavath's Oscar-nominated documentary about Laos is called “The Betrayal,” though a more apt title would pluralize it, to “The Betrayals.” The film — heart-tugging, poetic, agonizingly real — begins in the ‘70s, as the U.S. launches its covert war in Laos, in an effort to contain the spread of Communism through Southeast Asia. Despite the physical devastation — the film notes that America dropped more tons of bombs on Laos than it used in World Wars I and II combined — the war is eventually recognized as futile, and the U.S. withdraws, abruptly and totally, leaving its Laotian allies to deal with the brutal aftermath. The Phrasavath family, which had fought alongside the Americans, must flee their country, and face betrayal number two: The U.S., where they settle, is not exactly the land of freedom, opportunity and endless electricity. In Prospect Park, Brooklyn, they reckon with poverty, Asian gangs and, worst of all, the disintegration of family that was the core of life back home. Powerful and insightful, “The Betrayal” shows Wednesday through Friday, Nov. 11-13, at the Wheeler Opera House.