How can the U.S. Constitution be defended?
http://www.teaparty911.com/issues/defending_the_constitution.htm
So if you’re a federal employee, and you wonder just what your oath actually means
You have to stay loyal to the government that is based on the Constitution, and you can’t support a rebellion or overthrow of that government.
https://www.washingtonpost.com/news/volokh-conspiracy/wp/2015/01/12/you-promised-to-defend-the-constitution-against-all-enemies-foreign-and-domestic-now-what/?noredirect=on&utm_term=.fa05c9a7a008