Yes, and yes. I was a voting rep in my unit many times throughout my Air Force years... not only do trainees get this guidance, but everytime a major election comes around, everyone gets a reminder NOT to endorse candidates or engage in partisan politics while in uniform. However, you may, in uniform, make a point about the importance of exercising voting rights.
(Now... WITHOUT the inadvertant underlining)
“How often does the military remind service members against the prohibition of campaigning while representing or even appearing to represent the US military? Basic training? At the start of every election season?”
Yes, and yes. I was a voting rep in my unit many times throughout my Air Force years... not only do trainees get this guidance, but everytime a major election comes around, everyone gets a reminder NOT to endorse candidates or engage in partisan politics while in uniform. However, you may, in uniform, make a point about the importance of exercising voting rights.
I saw a posting in another thread on this subject that service members could participate in a campaign rally as spectators while in uniform. From what I read about this incident elsewhere, he wasn't there to appear, but was called up on stage by the candidate.
Yes, both he and the candidate (or at least the candidate's campaign staff) should have known better. But, that would be an uncomfortable invitation to refuse.