The White House fired a senior nuclear non-proliferation official for anonymously tweeting insults about powerful people. See examples and commentary. How senior? A search engine result from Princeton names him "the director for nonproliferation at the National Security Council"; the page has already been deleted. Reports suggest that there was an internal investigation to find him, and differ on whether he had said anything to threaten national security. None mention anything suspicious, but one has him under investigation by the DoJ. Most reports say he is in trouble for embarrassing the wrong people.
Edit: In what sounds like a related story, the Department of Health and Human Services fired the woman who had the misfortune to answer the phone when Sean Hannity called the healthcare telephone line. The call center might technically be run by a contractor, but the order to fire her certainly came from a political officer.