“Canal Zone” sits at the apotheosis of Wiseman’s 1970s work. The specter of Vietnam (which looms over his early features “High School” and “Basic Training”) haunts the proceedings. And in the setting, the U.S.-controlled Panama Canal Zone in 1976, shortly before two treaties established a path to turn over the area to Panama, the director finds a surreal simulacrum of American life. Wiseman repeatedly reminds us that he was shooting during the United States’ bicentennial year, and he plays on the cognitive dissonance of celebrating national values amid what critics saw as an imperial endeavor. Early on, a cleric, delivering an invocation at a Canal Zone district court, asks a divine power to move “our executive, legislative and judicial authorities to reflect on the noble motives which first inspired our Declaration of Independence and Constitution.”