(CNN) Roy Cohn tells an interviewer his legacy is inextricably linked to the Army-McCarthy hearings, but it's impossible to watch "Where's My Roy Cohn?" without seeing the red-baiting attorney and fixer through the prism of the current President of the United States.

Director Matt Tyrnauer's documentary zeroes in on Cohn as a mass of contradictions, a closeted gay man who denied that he had AIDS until his dying day, described by his cousin as a "self-hating Jew," and known for his ruthlessness and determination to win at all costs.

The most salient feature in light of Cohn's relationship to Donald Trump, however, is his commitment to spinning out his own version of events -- to always claim victory in any situation, even those that are demonstrable losses or setbacks; and to never apologize or admit to being wrong.

Joseph McCarthy and Roy Cohn during a committee hearing (Photo by AP/REX/Shutterstock 6648726a)

Those who have studied Cohn likely won't learn a whole lot new from the film, but that doesn't make its lessons any less significant, or the narrative as a whole -- given its relationship to current events -- any less enlightening as a road map to Trump's public-relations philosophy.

Those familiar with the famous rebuke of Sen. Joseph McCarthy at the Senate subcommittee hearings, for example -- attorney Joseph Welch eviscerating him by asking, "Have you no decency, sir?" -- might be shocked to see additional footage, in which the senators and lawyers made snide insinuations about Cohn, McCarthy's chief counsel, and his relationship with G. David Schine, after Cohn lobbied to obtain special privileges for the Army private.

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