Don't forget the doctrine of "qualified immunity". Police officers/departments carrying out their official duties can only be sued for violations of "clearly established" law. Seems maybe reasonable in theory, but in practice means that even if they do something obviously, blatantly illegal, they can avoid consequences if they can argue that the specific set of factual circumstances had not previously been judged to be a Constitutional violation.
Here's one case that recently came to my attention: https://www.theusconstitution.org/litigation/micah-jessop-br...
The plaintiffs allege that, while executing a search warrant, Fresno police officers personally stole several hundred thousand dollars worth of coins. The Ninth Circuit Court of Appeals decided that even if this theft happened, the officers could not be sued:
> We recognize that the allegation of any theft by police officers—most certainly the theft of over $225,000—is deeply disturbing. Whether that conduct violates the Fourth Amendment’s prohibition on unreasonable searches and seizures, however, would not “be ‘clear to a reasonable officer.’” [...] Because Appellants did not have a clearly established Fourth or Fourteenth Amendment right to be free from the theft of property seized pursuant to a warrant, the City Officers are entitled to qualified immunity.
Yesterday the Supreme Court declined to consider the plaintiffs' appeal, which means they're SOL.