Not the police. This is already well established legally that police do not have a duty to protect. This is why 2A rights are so important, because the only person morally, ethically and legally responsible to protect you is you.
I've seen videos of European or UK officers dealing with knife wielding nutjobs by using their riot shields to form a Roman phalanx to enclose and surround the nut job until they drop the knife. I just think we might be doing it wrong.
The police have not duty to protect any ONE individual but a duty to protect society as a whole. That is why they have a duty to stop this guy BEFORE he hurts any other citizen.
I’ve seen the video of the UK cops with the shields and those officers are flipping idiots to even accept such use of force policies. The only reason they do is because not enough of them have not been killed or injured.
Now on the other hand, 60k cops in the US are assaulted each year, 10k required hospitalization. Police work is hands down the most dangerous job FOR WORKPLACE VIOLENCE.
http://www.bjs.gov/content/pub/pdf/wv09.pdf