In many places, you don't need approval from unions, but if you don't get it you have to have City Council or a Mayor with the stones to call the unions' bluff when instituting policies. Spokane, WA, could have had an independent police ombudsman's office in the wake of Officer Karl Thompson killing Otto Zehm, a mildly mentally impaired (and completely innocent of wrongdoing) man whose dying words were "I only wanted a Snickers." Unfortunately, it was put into place without any independent investigative or disciplinary powers because our political leaders didn't have the guts to tell the unions to put up or shut up.
Basically, the Ombudsman asks, "I'd like to get an account of what happened."
Cops reply, "Nah, we'd rather not."
Ombudsman: "Oh, okay. See you tomorrow!"
The unions said they wouldn't budge on investigative powers, and under Washington law the contract framework under which officers can be disciplined cannot be changed without the consent of the union. So the city waited until their contract was up. The union said, "No, we'd rather not." And the City Council & Mayor blinked, and deleted the provision from the new contract. Now we have to wait for the new contract to expire before getting another chance at independent oversight. Unions were great when they were fighting for humane working conditions. Now they're mostly around to protect things that should be open to competition. The places that need unions don't have them, and the places that have them don't need them. The only States where they work how they should (where unions have to balance the concessions they wring from employers with competition from local, non-union workers. Right-to-work States are where it's at, because unions can't force membership as a condition of employment. They have to provide a compelling reason for employees to join.
(And to head this stupid argument off, right-to-work does not mean "Your employer can fire you at any time without cause." Stop parroting that tired lie, because that's what's called "at-will employment," not right-to-work.)