Having just crashed his bomber into the Pacific, George H. W. Bush floats toward a Japanese island called Chichijima, where he expects to be detained and tortured. Instead, a U.S. submarine comes by and pulls him out of the sea.

“I wonder if I could have done something different,” Mr. Bush said in 2003, recalling his military service during World War II. “Why me? Why am I blessed? Why am I still alive? That has plagued me.” In an interview for “The Bush Years: Family, Duty, Power,” the six-part docuseries airing on CNN, the former secretary of state Colin Powell claims this incident drove Mr. Bush into public service.

We Americans eat myths for breakfast, lunch, dinner and dessert—and in “The Bush Years,” CNN adds a thick layer of glaze to the Bush legacy. The show opens with a staticky, black-and-white, James Bond-ish title sequence, replete with furrowed brows and oil rigs. The clan is presented as a set of WASPy, earthier Kennedys, “one extraordinary family, fueled by ambition, driven by duty.”

We Americans eat myths for breakfast, lunch and dinner—and in “The Bush Years,” CNN adds a thick layer of glaze to the Bush legacy.

Maybe in the Trump era, “duty” is a more appealing concept than ever. It is apparent from watching the series that George H. W. Bush was more tactful and level-headed than President Trump. He also called for a “kinder, gentler nation,” signing into law the Americans with Disabilities Act of 1990 and the Immigration Act of 1990, which expanded access and opportunity in the United States for millions of citizens and foreign workers. But as we come to grips with a national history of violence, greed and racialized privilege, this fable of noblesse oblige rings hollow.

First comes the Texan origin story. “He just couldn’t bring himself to go to Wall Street,” says his brother, a bow-tied Jonathan Bush, who is one of the series’ primary interview subjects. “He wanted to go off and do something on the frontier.” So he decamps to the flatlands of Texas, where he and his wife, Barbara, live in a duplex next to a mother and daughter, who, we are told, happen to be sex workers. Despite their Greenwich, Conn., pedigree, the Bushes are “making it on our own” out West.

Nothing captures the family’s privilege more than the footage in Episode 1 of Prescott Bush, George’s father, being sworn into the Senate next to John F. Kennedy. President Eisenhower even places Prescott Bush on a list of possible successors. Joe McCarthy, Prescott’s foe in the Senate, is presented as a Trumpian figure who will teach H. W. to stand up to bullies.

As we come to grips with a national history of violence, greed and racialized privilege, this fable of noblesse oblige rings hollow.

In another eyebrow-raising moment, Barbara Pierce Bush, the daughter of George W. Bush, says of her grandfather’s ascension to the presidency: “When our grandfather became president, I asked my friend when her grandfather’s inauguration would be. I thought that everyone’s grandfather had one.”

As the historian Jeffrey Engel remarks in the documentary, Mr. Bush relished his proximity to power; he loved being in the same room as Mao Zedong, for instance. And he stayed loyal to Richard Nixon for longer than most. “When he says, ‘I had no knowledge of Watergate,’ I believe him,” H. W. told his brother Jonathan.

George W. Bush receives a sympathetic portrayal in the series. Described as “kind of all over the place” in his youth, W. burns like a “Roman candle,” to quote an article by the New York Times columnist Maureen Dowd. He goes into the Texas national guard to gain military experience, a strategy, some say, to avoid having to serve in Vietnam. Unlike his father, he is a ne’er-do-well, a disciple of “beers, blended drinks and barbecues.” Under pressure to live up to his father’s legacy, he gets religion and transforms his life, giving up drinking at age 40. Running for high office, he rises to the occasion, according to the series, beholden to ambition and, supposedly, duty.

Decency and “duty” can be hard to parse—abstractions applied to people who talk pretty and use summer as a verb.

But decency and “duty” can be hard to parse—abstractions applied to people who talk pretty and use summer as a verb. The documentary sometimes conflates these qualities with centrism. H. W. was an anti-communist who favored deregulation and birth control. Throughout his career, he triangulates, running for the Senate as a conservative in 1964 to ride the Goldwater wave that never comes and rejecting the Civil Rights Act. It is not until he realizes black veterans are being discriminated against that he voices support for civil rights.

During one of his interviews for the documentary, H. W.’s son Neil Bush says: “My father believed and said that African-American men and women who served their country in Vietnam or any other war deserved to come home and be treated fairly. Simple as that.” It is unfortunate that he did not have this revelation before black people were sent in disproportionate numbers to die in Southeast Asia.

Other times, duty manifests itself in even-handedness and calm. After the fall of the Berlin Wall, H. W. does not strike a triumphant tone. “It would not have been in his character for him to start shouting and screaming,” says Mr. Powell, a comment that comes off as an implicit criticism of the current occupant of the White House. “It’s just not him.”

“The Bush Years” is about the preservation and reproduction of power—and that story is getting kind of old.

Former Vice President Dick Cheney, H. W.’s secretary of defense, calls the 41st president’s handling of the post-Cold War era “masterful.”

“He managed to be thoughtful, generous and at the same time understanding of the problem for Gorbachev’s perception,” says Mr. Cheney.

The series provides some critiques of U.S. power, as when the historian Leah Wright Rigeuer talks about the chasm between the U.S. and Iraqi experience of the Gulf War. For the most part, however, U.S. militarism and global dominance are taken as givens. Do prudence, humility and civility mean anything when, ultimately, they are used to enact violence? Does it matter that “the president tosses and turns the night of the [Gulf War] beginning,” as the documentary tells us?

The racist Willie Horton ad is written off as a political tool, with criticism sandwiched between defensive commentary. Mr. Bush’s secretary of state and chief of staff, James Baker, remarks: “George Bush understood that politics was a bloodsport. He was willing to get out there and do what he needed to do by way of going on the offense and that sort of thing when he had to. But he wasn’t particularly comfortable with it.”

We are meant to view one of the most powerful families in U.S. history with sympathy, to understand who and what made them. This is one of the joys of biography, but the CNN documentary veers too far into hagiography. Watching it, I kept thinking of this passage about the Trump inauguration from Emmett Rensin’s review of Hillary Clinton’s 2017 memoir, What Happened:

It is no mistake that the book begins with former presidents of all parties brought together by wariness of the newest member of their club, how they console one another with social offers, how above all they are civil to one another, how more than half of them come from only two families. This is a book about how power preserves and reproduces itself.

“The Bush Years” is also about the preservation and reproduction of power—and that story is getting kind of old.

Brandon Sanchez is an audience voices reporter at The Wall Street Journal. Previously, he was an O’Hare fellow at America.