Wire reporting: (AP, via KSL)

President Donald Trump on Thursday signed a proclamation establishing the Oval Office, the Outer Oval Office and the Cabinet Room as the Oval Office National Monument under the Antiquities Act^1,2.

The White House said the Interior secretary must develop a management plan that prioritizes preservation and must document, review and consider alternatives before substantially altering or demolishing the spaces¹.

Trump described the step as blocking anyone from ripping the rooms down to build something in a slightly different shape³.

The proclamation, as reported by BBC and CBS, says it does not restrict a president's authority to redecorate, select furnishings or make ordinary operational and security modifications that do not substantially impair historic structure or architectural character^3,4.

CBS News reported that the action does not stop a future president from restyling the office or from reversing the designation, noting Trump has reversed monument designations made by predecessors⁴.

Trump said no major modification would occur without congressional approval and that he would send the designation to Congress to be ratified^2,6.

CBS reported that a requirement for congressional review of major changes is not in the document's text⁴.

The White House is already a National Historic Landmark; the proclamation argues the Oval Office still merits separate protective management as a discrete historic structure^1,3.

BBC reported that Congress has carved out an exemption to the National Historic Preservation Act so presidents can make needed changes, and that the current Oval Office dates to the early 1930s under Franklin D. Roosevelt³.

Greg Werkheiser of Cultural Heritage Partners told BBC that furniture and decor remain at a president's discretion if permanent art and architecture are not damaged³.

ABC News and States Newsroom placed the signing after Republican losses in both chambers of Congress this week, as Trump also highlighted a White House ballroom after the East Wing was demolished and other D.C. construction^2,6.

CBS reported that Sen. Richard Blumenthal, the top Democrat on a Senate investigations subcommittee, sent letters Thursday to known donors to the ballroom project⁴. What a later Congress or a successor administration will do with the designation, and how Interior's management plan will work inside a working White House, was not settled in Thursday's papers^1,4,6.