Can the President require government employees to sign an NDA?

[LetterRip]

Apparently Trump has required administration employees (White House staffers) to sign NDA's - can they have any legal force?  I would think they would be null and void.

President Donald Trump required senior White House staff members to sign nondisclosure agreements that not only threatened stiff financial penalties for violations, but extended far beyond Trump's time in office, Washington Post columnist Ruth Marcus reported on Sunday.

According to a draft agreement Marcus said she viewed, violators could face $10 million penalties for each unauthorized release of "confidential information," though it's possible the final NDAs reduced the penalty amount. The agreement applied not only to staffers' White House tenures but "all times thereafter."

http://www.businessinsider.com/trump-nondisclosure-agreements-white-house-staffers-penalties-2018-3

[TheDrake]

The ACLU doesn't think they are enforceable.

NEW YORK — President Trump reportedly had senior White House staff members sign nondisclosure agreements at the start of his administration, according The Washington Post.

Ben Wizner, director of the American Civil Liberties Union’s Speech, Privacy, and Technology Project, had this reaction:

“Public employees can’t be gagged by private agreements. These so-called NDAs are unconstitutional and unenforceable.”

[Seriati]

I'd think that the answer might be yes, but not where they conflict with the requirement to maintain and create government records (which themselves are subject to FOIA requests), nor to the extent they would interfere with an subpoena or other required disclosure.

On the other hand, it might be an illegal condition on government employment.