The US Supreme Court ruled in Town of Castle Rock v. Gonzales and DeShaney v. Winnebago County that the police could not be sued for failing to protect citizens, as no such constitutional obligation exists on their part. This has been used by gun advocates as an argument for expanding the right to own guns in the US.
On the other hand authorities in countries such as Japan or the UK frequently claim that citizens have no reason to own guns for self-defence, as they could always call the police for help instead. But could the police actually be sued in those countries for failing to carry out their responsibilities? If not, what reasons have been given for simultaneously preventing citizens from protecting themselves and failing to redress situations where the police fails to protect individuals?