The elected office of sheriff, being a law enforcement office, can push back at the county level to overreaching state government, in a similar way to how state government through states' rights can push back against an encroaching federal government. It's a power of government that is closer to the people and more accountable to them, theoretically. Not to say it can't be abused but it can also serve a valuable role in checks and balances. Look up the principle of the Lesser Magistrate.