LMAO this you?
Uhm you challenge their authority in court with a lawyer present or in the laws themselves via politicians. If you want to physically challenge a cop when he's in front of you trying to arrest you and barking orders with a gun on his hip and a license to shoot you if you resist have fun getting shot. Apparently you're cool with people getting into street fights with cops LOL, great advice!
I was also careful to say "lawful orders". You're also free to verbally challenge a cop's authority if he's giving you unlawful orders (or lawful ones, though that will do nothing). I've watched about a billion Youtube videos of "police audits". A cop is extremely unlikely to shoot you or even arrest you if you're just running your mouth and calling them on their BS, especially with a camera rolling. But if you're going to actually DO something stupid, like run, or reach for your waist, or otherwise resist arrest well congrats you're effed.