The Smithsonian Institution is sometimes called the nation’s attic. That description is inadequate. An attic stores things. The Smithsonian does something far more consequential: It helps Americans understand who we are.

That responsibility carries particular weight as the United States celebrates its 250th anniversary and the Smithsonian prepares for new leadership. The transition comes amid an intense debate over how the Smithsonian presents American history. A White House review criticized the National Museum of American History, arguing that ideological concerns have displaced an understanding of history as a shared national inheritance.

Smithsonian leaders and historians have defended the institution’s scholarly independence and warned against allowing political power to dictate how history is told. The answer cannot be choosing one of those impulses and ignoring the other.

TRUMP V. SMITHSONIAN: A TIMELINE OF HOW THE WHITE HOUSE FIGHT OVER 'WOKE' HISTORY UNFOLDED Outgoing Smithsonian Secretary Lonnie Bunch recently said the Smithsonian must show both the light and the dark. He has also described America as an ideal as much as a place — an aspiration toward liberty, fairness, justice and equality. But has the Smithsonian been telling the American story fairly?

The harder question is one of proportion: How should America’s national museums put the light and the dark together into an honest account of the country?

I have spent much of the past quarter-century helping govern museums and historic institutions in Virginia. That experience has convinced me that historical integrity requires more than factual accuracy. It requires proportion, context and perspective.

America’s national museums should tell our history honestly, including our shortcomings, contradictions and occasions when Americans failed to live up to the principles proclaimed at the nation’s founding. But those failures should not become the organizing principle through which the American experience is understood. Viewed in proportion, the American story is extraordinary.

A collection of colonies declared that human beings possess rights governments do not grant. Americans then built an enduring constitutional republic around representative government, individual liberty and the rule of law. Those ideas changed human history.

The nation they produced survived civil war, expanded freedom and political participation, welcomed generations of immigrants, became an industrial and scientific power, defeated fascism and Soviet communism and put human beings on the moon.

When America fell short of its founding principles, succeeding generations repeatedly returned to those principles to demand the nation do better.

There is an important distinction between examining America critically and teaching Americans to regard their country cynically. A great national museum should be capable of the former without succumbing to the latter.

Museums inevitably make choices: which objects to display, which stories to emphasize and which context visitors receive. Individual facts can be accurate while their cumulative presentation leaves a distorted impression.

The Smithsonian should resist any interpretive approach that begins with contemporary political or ideological categories and works backward through history to validate them. History should illuminate today’s debates, but the past deserves to be encountered on its own terms. Nor can the answer be replacing one political orthodoxy with another.

The Smithsonian has endured presidents and Congresses of both parties. Its credibility rests upon scholarship, independence and public trust. Americans should never believe exhibits in their national museums are rewritten whenever political power changes hands.

James Smithson envisioned an institution devoted to the "increase and diffusion of knowledge." Two centuries later, the Smithsonian holds objects that belong to all of us: General George Washington’s uniform. President Abraham Lincoln’s hat. The Star-Spangled Banner. The Wright Flyer. Harriet Tubman’s hymnal. The Greensboro lunch-counter stools.

The Apollo 11 command module. They tell a remarkable story of aspiration, struggle, achievement and progress. No curator owns that story. Neither does a president, political party, academic movement — or generation. We hold it temporarily in trust. That principle matters especially during America’s 250th anniversary. This milestone should invite reflection. But reflection is not national self-reproach.

Our semiquincentennial should not become a 250th-anniversary wake, principally devoted to cataloging America’s shortcomings while treating its achievements as qualifications or afterthoughts. There is too much worth celebrating.

Visitors should leave the Smithsonian knowing America’s history more fully. They should understand our shortcomings and contradictions, but also our achievements. They should leave impressed by what Americans built, moved by what Americans sacrificed, grateful for what they inherited — and challenged to preserve and improve it. They should even leave proud.

Pride in one’s country is not the enemy of historical understanding. Properly grounded in truth, it can be one of its products.

The Smithsonian need not tell Americans what to think about America. It should give them the artifacts, scholarship, context and perspective necessary to understand the inheritance that belongs to them.

Tell the hard stories. Tell the great ones, too. Trust Americans with both.

After 250 years, the American story remains unfinished. The Smithsonian’s responsibility is to preserve it faithfully, interpret it honestly — and ensure the next generation understands why it remains a story worth celebrating.