Ok, but in the US they are not obligated to do that. It's been put forth to the Supreme Court at least once. A cop can be at the scene of you getting actively

Ok, but in the US they are not obligated to do that. It's been put forth to the Supreme Court at least once. A cop can be at the scene of you getting actively murdered and do nothing about it, and legally the cop is ok. Morally, you could definitely argue they're not okay.