Christopher Nolan’s powerful biopic “Oppenheimer,” now playing in Imax (where we saw it), delivers a powerful punch at nuclear politics and the McCarthy era.

There seemed to be a Communist in every closet. And “Oppy” was accused of being one of them. He was put through hell, this after being touted “father of the atomic bomb,” and helping to end World War II with the Japanese.

Most poignant were the scenes when his former allies and supporters turned against him and accused him of being a Communist spy.

Oppenheimer literally contributed to making the world safer for democracy and averting worldwide nuclear annihilation. His reward was a “slap in the face with a wet bathing suit,” as a professor friend of mine used to say.

Stripped of his security clearance, Oppy was left incapacitated — and frustrated in scenes with his detractors and his own family.

There is a parallel between “Oppenheimer” and “The Imitation Game.” During World War II, Alan Turing, the English mathematical genius, tried and succeeded in cracking the German Enigma code with help from fellow mathematicians while hiding his own homosexuality, for which he was later condemned.

Like Oscar Wilde, the celebrated playwright, Turing was ostracized and persecuted. So, too, was Oppenheimer, who, in scenes, was called before committees determined to disgrace him.

And, as was Oppenheimer, ultimately, if belatedly, Turing was vindicated — by government.

This observer would hope to see Cillian Murphy as Oppenheimer nominated for an Oscar (if the Academy of Motion Picture Academy of Arts and Sciences can remember come nominating season) and, as is the buzz, Robert Downey Jr. as the villainous and jealous Lewis Strauss (or “Stross,” as Strauss affected it).

More kudos go to Emily Blunt as Kitty, Oppenheimer’s alcoholic wife; Matt Damon as Col. Leslie Groves, who hired Oppy and later turned on him; Gary Oldman as President Harry S Truman (no pleasant soul he, who dropped The Bomb); Florence Pugh as Jean Tatlock, mistress to the quantum physics scientist, and Tom Conti as the enigmatic Albert Einstein.

Pictures like “Oppenheimer” must be made, not only to capture history but to reveal the American state of mind that produced that history. And such films may be three hours long, which is the common complaint heard about “Oppenheimer.” But like “Titanic,” “Oppenheimer’ is absorbing and mostly entertaining. Audiences identify with Oppenheimer and feel his pain.

Altogether, “Oppenheimer” stands as a major achievement in cinema. Nolan did a superior job in his writing and directing of the film, and if it makes billions of dollars, that’s okay, too.

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