In the United States, there is something called a separation of powers, which includes a lawmaking branch of government that makes the laws and a judiciary to review the constitutionality of laws. Local police officers and sheriffs were never given a veto power over our civilian government per the U.S. Constiution, fortunately. And as mentioned, there were periods in history, especially during fuedal times, when the local sheriffs were judge, jury, and executioner. A gun and a set of handcuffs is not nearly the same as legal training, popular election, or appointment to a judgeship.
Absolutely! You need years of legal training from "experts" such as Elena Kagan and Laurence Tribe to learn that "the right of the people to keep and bear arms shall not be infringed" refers to a "collective right," while due process creates "penumbras and emanations" that create a Constitutional right to sodomize whomever you want or to kill your unborn baby at any stage of gestation.