Can you defend yourself if a cop decides to kill you?

Bad Elk v. United States, however, upon further reading, this has been all but overturned by pretty much every state during the backlash against the Civil Rights Movement, under the reason that you should sue if you're unlawfully arrested. But then qualified immunity happened. So I retract my statement. Cops can do whatever they want to you and you have no legal recourse. The only way any cop will receive any punishment is if enough media attention is given to that case.