One of the two entrances with the painting of President George Washington featured which is part of the reopening of The Presidents Hall's most popular exhibition on the American presidents at the National Portrait Gallery. (Astrid Riecken)

Nothing seems stable, dignified or unifying about the presidency these days, which is what makes the newly designed “America’s Presidents” exhibition at the National Portrait Gallery such a relief. Closed since early this year, the rooms devoted to portraits of this country’s chief executives (and sometimes their wives and family members) have been reinstalled for the first time since 2006, with new carpeting, lighting, window treatments and touch-panel information screens. Some of the works on view are different, and all of the wall texts have been rewritten. Given the way so many museums are going today — toward entertainment and trivial educational agendas — one couldn’t help but wonder what the Portrait Gallery would do with one of its most beloved, and most important, hallmark exhibitions. The good news: The curators went for substance.

Only keen-eyed observers with prodigious powers of memory will detect significant differences between the labels for the new exhibition and those from 2006. They are all new, but differ mainly in details and small matters of inflection. James Polk, who spurred the country into war with Mexico and stole a million square miles of new territory, was noted in the previous show for his diligence and accomplishment in office. He is now called “one of the most consequential presidents in American history.” There are also substantial tweaks to the discussion of Woodrow Wilson, including this: “Recent scrutiny has drawn attention to his regressive actions with regard to women’s voting rights and other civil liberties.” And, finally, the legacy of Ronald Reagan includes mention of one his most destructive failures: “His conservative stance led him to largely ignore the AIDS crisis.”

Changes to the works on view are also surgical. A Gilbert Stuart painting of Thomas Jefferson, co-owned with Monticello, is now back at the president’s stately home until 2019 while the portrait gallery uses a fine painting of a still-young Jefferson by Mather Brown. The previous iteration included a Thomas Stephens painting from the gallery’s collection that depicted Dwight D. Eisenhower in military uniform; the new show includes a borrowed painting by the same artist showing Eisenhower from his time in office.

But all of the favorites are still here, including Elaine de Kooning’s sun-dazzled vertical portrait of John F. Kennedy, as energetic as an adolescent in swim trunks, and the series of mid-19th-century presidential portraits by George Peter Alexander Healy, an underappreciated artist and the painter with the most works in the exhibition. Peter Hurd’s 1967 portrait of Lyndon B. Johnson, showing the president against a brilliant sunset sky, is also back and still it baffles why the 36th president called it “the ugliest thing I ever saw.” One wonders if this is more a reflection on his inner life than a comment on the artist’s work. Given what the nation is now remembering about Johnson, from the Ken Burns Vietnam documentary, Johnson might welcome the artist’s radiant depiction of his power and vision.

And the beloved Gilbert Stuart “Lansdowne” portrait of George Washington, a fascinating hybrid of American iconographic references with European painterly style created for an English aristocrat, is also back, newly restored and resplendent in the new lighting. Its brilliant white linens and Tiepolo blues make it seem as if the black-clad Washington has teleported into some Napoleonic-era palace, a grim, sober interloper from a humorless land of republican virtue.

So why undertake a renovation of the show if the message is substantially the same? Kim Sajet, director of the gallery, said, “Frankly, it was looking a little tired.” She wanted to refresh the space, and a reboot allowed the museum staff to look into conservation issues. They also removed some of the visual trappings of old-world power — the red carpets and heavier case work — in an effort to breathe a little more light and air into the rooms. The addition of Spanish-language labels opens up the exhibition not just to citizens of the world’s second-largest Spanish-speaking nation — the United States — but to visitors from other Spanish-speaking countries and Americans who take pride in our increasingly bilingual culture.

The Portrait Gallery is a constant paradox: Its focus on America and portraiture makes its mission inherently conservative, yet for years now it has been one of the Smithsonian’s most consistently provocative museums, with exhibitions that explore gender, sexuality, race and difference. Perhaps that explains, indirectly, why it has taken such a studious approach to the new presidents gallery. For most visitors who come to Washington on the standard patriotic pilgrimage, the “America’s Presidents” gallery is the heart of the museum. They won’t be disappointed, or threatened by anything in this new layout. The history is solid, the approach is serious, and the tone, if anything, has less levity than the last version of the show.

And maybe that gives the gallery cover to continue doing what it should be doing, pushing the boundaries on who is included inside its walls, and the definition and meaning of portraiture. In this sense, perhaps the best summary of the show is to say that it is presidential, in a manner that is radically threatened by our current president, whose portrait will be added after he leaves office. The “America’s Presidents” gallery is a kind of official duty that the National Portrait Gallery must perform, an obligatory, ceremonial and largely beloved tradition that recalls the origins of the institution and its civic purpose. Planning for the show predates our current moment of crisis, but its unveiling arrives at a powerful moment of need. If you undertake civic ritual, you must do it with sincerity and aim for flawless execution. And the gallery has. You may quibble with details, but there’s no question that there’s a truer sense of the American presidency in this show, warts and all, than in the spectacle that is now sucking all the oxygen out of our public life.

America’s Presidents reopens Friday at the Smithsonian National Portrait Gallery, Eighth and F streets NW. 202-633-8300. npg.si.edu.