I don't think any current military regs cover that as a No Can Do, although I am eager to hear from any previously or currently serving member of the US Armed Forces on the subject...
Here lurkers...take this back to that idiot Kos Kiddie:
4.1.1.9. Attend partisan and nonpartisan political fundraising activities, meetings, rallies, debates, conventions, or activities as a spectator when not in uniform and when no inference or appearance of official sponsorship, approval, or endorsement can reasonably be drawn.
4.1.2.1. Participate in partisan political fundraising activities (except as permitted in subparagraph 4.1.1.7.), rallies, conventions (including making speeches in the course thereof), management of campaigns, or debates, either on one’s own behalf or on that of another, without respect to uniform or inference or appearance of official sponsorship, approval, or endorsement. Participation includes more than mere attendance as a spectator. (See subparagraph 4.1.1.9.)
4.1.2.3. Allow or cause to be published partisan political articles, letters, or endorsements signed or written by the member that solicits votes for or against a partisan political party, candidate, or cause. This is distinguished from a letter to the editor as permitted under the conditions noted in subparagraph 4.1.1.6.
4.1.2.5. Speak before a partisan political gathering, including any gathering that promotes a partisan political party, candidate, or cause.
http://www.dtic.mil/whs/directives/corres/pdf/134410p.pdfLike I said the only mistake the idiot made was posting that crap in his Cracker Jack outfit. But it's still a mistake that coule embarass his command and get his superiors in trouble.
Hence the reason they have to be notified.
ETA: This is the same kind of crap and same violations that got that idiot Paul supporter in deep kim-chee