A great observation!
Look at the top of the lamp, there's the edge of the door.
Now look at the floor. There is space between the door bottom and floor.
Sigh. It's a door.
From looking at several floor plans, it would appear that is the door to the President’s secretary’s office.
I agree. The photo ends at the top of the lamp on my computer, so I don’t see the door edge, but the gap at the bottom suggests it’s a door. Plus the woodwork on the bottom third of the door is misaligned before and after the lamp. That wouldn’t be the case if it were a continuation of the wall.
I would imagine whoever is in charge of like things at the White House has access to the best carpenters in the world. Why would it look like there’s at least a one inch gap between the floor and the bottom moulding?