The Supreme Court keeps a Missouri law on hold that bars police from enforcing federal gun lawsThe law would impose a fine of $50,000 on an officer who knowingly enforces federal gun laws that don't match up with state restrictions.
Source: The Supreme Court keeps a Missouri law on hold that bars police from enforcing federal gun laws (https://www.politico.com/news/2023/10/20/the-supreme-court-keeps-a-missouri-law-on-hold-that-bars-police-from-enforcing-federal-gun-laws-00122856)