On Thursday President Trump issued an executive order, “Restoring Truth and Sanity to American History.”

In Mr. Trump’s customary bluster, the order bursts with accusations against unnamed persons who are presumably my fellow historians and museum curators for our “concerted and widespread effort to rewrite our nation’s history.”

The order’s repeated invocation of the Smithsonian Institution echoes now-familiar right-wing goals outlined in Project 2025 and elsewhere: ending the alleged “woke” agendas on race and gender, creating “parents’ rights” and school choices and promoting history aligned with founders’ “values.”

According to the president, “objective facts” have been replaced with a “distorted narrative driven by ideology.” And then comes that penetrating epithet, the order’s organizing logic: the desire to end the “revisionist movement” carried out by unnamed historians.

I recall that a great historian, Prof. James Horton, used to have a poignant answer to this label: “Would you want your doctors not to be revisionists?” Any field of study must innovate to maintain relevance. The assumption that there is a standard, agreed-upon truth about the country’s past is a fantasy. But when declared by a sitting American president, it becomes a provocation and an insult.

The order is nothing less than a declaration of political war on the historians’ profession, our training and integrity, as well as on the freedom — in the form of curious minds — of anyone who seeks to understand our country by visiting museums or historic sites.