If the US had a normal, rational Administration, then yeah, I'd probably accept the "national security" explanation. But when the Administration claims completing the White House ballroom is a matter of "national security", and Antifa is the current largest threat to "national security", then credibility for these claims is completely lost.

> But when the Administration claims completing the White House ballroom is a matter of "national security"

All other things equal, opening a literal breach in one of the white house's exterior wall seems like it would cause a "national security" issue if the construction project was not finished and the hole remained gaping afterwards.