When I was a cop, I rather enjoyed swearing to uphold the constitutions of the United States and Maryland. It seemed like quite an honor. (Even if the actually oath was done very matter-of-factly in some cubical by a woman who didn't seem to care. And honestly, I've never read the Maryland Constitution.)
Oath Keepers is an organization set up to persuade America's police officers and soldiers to refuse to carry out unconstitutional orders. Fair enough. But somehow it's considered controversial and right wing.
There's an interesting interview with the founder, Stewart Rhodes, in Reason magazine.