Police have unions for negotiating better conditions but they don't displace power to the polices: police does not have right of strike. At best, what police officers can do is a strike of zeal, where they overlook most situations except for the most grievous.

This implies a speeding ticket will not get written but a bank robbery will be dealt with.

Again, the US is no example for anything, and even less for this.

Police is not a for-profit organization; it's a pillar of the democratic state and as such is moved by a mission not an production objective, which some ingenious politians and high ranking officers have tried to do, with horrible results, like police agents openly denouncing it to the public.

The checks and balances you fear will be knocked down are so scattered, it would take the complete dismantling of our entire country to remove it. Just recently, it was eliminated a specialized police tasked with immigration and border control and the back lash has been immense: people want specialized agents for specialized functions, regardless the previously dismantled force being disbanded for serious and proven cases of abuse of power and corruption, which led to arrests.

To prevent one force to feel unchecked we have three different polices, a plethora of specialized agencies and a central investigation department directly under the orders of the republic prosecutor. Too many people checking on too many people. This model works so well, even politians have been connected to serious corruption schemes lately.

We solved our war on drugs by removing the crime frame from consumption and carry for personal use, thus releasing police resources to contend with real traficking, not petty matters.

Take notes. Might be useful to someone.