With Robert Oppenheimer, the “Father of the Atomic Bomb,” a surprising subject of interest for this hot summer, Steve James’ “A Compassionate Spy” couldn’t be more timely.

The spy in question is Theodore Hall, a brilliant physicist whom Oppenheimer recruited in 1944 to join his Manhattan Project and make the first atomic bomb. Hall, who graduated from Harvard at 18, was the youngest physicist with the team.

Concerned about the bomb’s real-world legacy, at 19 he passed nuclear secrets to Russia.

“A Compassionate Spy” arrives as Christopher Nolan’s biopic “Oppenheimer” has become a blockbuster hit. Steve James, twice Oscar-nominated for his documentaries “Hoop Dreams” and “Abacus: Small Enough to Jail,” wrote, directed and edited “Spy.”

“I hope that all the attention to Oppenheimer and all the people watching it will come away, curious to know more,” James, 68, said in a phone interview yesterday.  “It’s such a fascinating story.

“At the ripe old age of 19, Ted makes this momentous decision to do what he did. And it’s just remarkable to me that someone so young, would do something so profoundly risky and impactful.

“And then on top of that, going in 2019 to Cambridge (England), meeting his wife Joan, this amazing woman who was then 91 (she passed away this year at 94), and her talking about her husband!

“I came away from that first shoot saying, ‘This is a story of espionage and geopolitics and war and bombs. But it’s also a love story between these two people.’”

James acknowledges that his “Spy” is, well, a compassionate take on Ted Hall’s traitorous acts.

As to how Ted escaped the same sort of trial and execution as fellow atomic spies Julius and Ethel Rosenberg, the film makes clear that when the FBI broke the Soviet’s secret code, they discovered Ted Hall’s betrayal.  But they couldn’t use that against him because it would reveal that the US intelligence community had broken the code.

“Because that was inadmissible in court,” James said, “they really needed Ted to give them something — and Ted was extremely careful and didn’t give them anything.”

One of the film’s most dramatic scenes, James emphasized, really happened. “When the FBI came calling in 1951 he was 25. The FBI knew everything from having broken the code, yet he is very calm and collected. When he realizes that the best thing for him to do is to stop cooperating, he got up and just walked out of the interrogation.

“That’s not a made-up story for dramatic purposes.”

“A Compassionate Spy” streams on VOD Aug. 4