I always wanted to join to do some good, but I had the same problem. I figured the only thing I could do is Secret Service and make sure I stay of protection detail, just get counterfeiters. I have a family member who joined the sheriff's department in a large city, and had to quit for ethical reasons.
and you were tasked with enforcing a law that violated the constitution, then either your oath would require you to rectify the situation or you should remove yourself from office.
Since it's not your job to decide constitutionality, the only honorable thing to do is resign. Never forget that your constitutionality is another's unconstitutionality. What if a law came out tomorrow subjecting doctors and mothers involved in abortions to prison sentences. Many cops and prosecutors can say "That law's wrong as it violates the right..." and not enforce it.
There has to be only one official voice on that subject concerning enforcement (there is jury veto, but that's not in enforcement, that's the people speaking).
I believe this is true about some laws, but not about all of them. What if there were a law that stated you could not comment in public about a candidate running for office. Can *anyone* doubt the constitutionality of such a law? Alas, in this era of lost common sense, some probably would think such a law was justifiable.
The only flaw in our form of government is that it requires a morally upstanding people to make it work.
Tuor