It isn't violating that pledge when the other Party, the FedGov, is no longer the same entity we all Pledged to in the first place.
I appreciate your feelings in this matter and I share them. I did not pledge allegiance to this govt either. I pledged allegiance to the republic of the US of A. That is why we need to stay and fix it, not give up and secede.
Btw, I deeply appreciate your service as a US Marine. Thank you for serving. My future son in law is currently enjoying an all-expenses-paid vacation over in the Helmand province as a Marine 1st Lt. The work you Marines do is so incredibly important. Now we need to vote out the current CiC and put in someone who understands what it is that you and other Marines are all about.