Educate me on a Sheriff or Counties power to not enforce laws?

[losttrail]

As I understand it, and I am not a lawyer nor a legal expert, the county sheriff is the top law enforcement officer in their respective county. As such they wield the law enforcement power and even the feds must obtain the sheriff's permission to execute enforcement within the sheriff's jurisdiction.

If this is correct, then the sheriff would have discretion to judge whether an order would be lawful or unlawful and thereby whether to enforce said law or not.

I know that the oath I took when joining the military specified "lawful orders" of those appointed above me and that I was to defend the Constitution against "all enemies, foreign or domestic."

Remember that the Constitution is the "law of the land" and should be our reference. Many laws have been passed and later found to be unconstitutional, so just because a law gets signed into effect, does not necessarily mean it is "lawful".

I would love for someone with the legal expertise to jump in here.