He told reporters on Thursday the space would not be allowed to be touched by anybody, destroyed or ripped down by stupid people in order to build something in a slightly different shape.
A former real estate developer, Trump has drastically altered the look of the president's official office during his second term, most notably by adding many gold features.
World leaders who have visited in recent months have complimented his decorative changes to the room, he added.
The current Oval Office has existed since the early 1930s, after its conception by President Franklin D. Roosevelt.
On the one hand he's talking about the importance of preserving the Oval Office — which is legally meaningless because he can't do it — and on the other hand he is absolutely taking an axe to the law that allows us to preserve other historic sites, one critic said.
The document also says it does not restrict the president's authority to redecorate the monument, select furnishings, or make ordinary operational and security modifications that do not substantially impair the monument's historic structure or architectural character. Critics said the move was legally meaningless because a president cannot bind successors in that way, while arguing the administration has shown disregard for other historic sites in Washington.
Trump said the order would make it impossible for anybody ever to destroy this incredible space. He called the Oval Office a special place and a symbol of the country and its greatness. Through lawsuits, they said, it has attempted to undermine laws that require preservation of those sites.