If I understand you correctly, are you really saying that getting a prosecutors case not thrown out of court a few years later is "a direct incentive" to a police officer, but personal liability for the same officer would not be a direct incentive ?
Note that in the parent post I'm explicitly mentioning direct criminal action against the officer personally, not compensation claims against the police district; as far as I understand, fines are not an option for felonies in USA, and even the lightest possible 'guilty' sentence would automatically get such policemen out of their jobs after the first such act.
Yes, that's what I'm saying. Getting cases thrown out frequently is an embarrassment to the police force as a whole. Whereas getting fined for the wrongful doings of a police officer is usually just a slap on the wrist for the police department, and it's paid out of taxpayer money.
Sure, having criminal action against the officer personally would be nice, but it seems as though it practice that's much easier to erode than the fruit of the poisoned tree doctrine. After all who polices the police? At least with a doctrine like that you have a different branch of government handling it. In any case prosecuting police for violating the law is not mutually exclusive with the fruit of the poisoned tree doctrine, both are nice things to have.
I really don't see any downside to the fruit of the poisoned tree doctrine. If police are doing their job as they should it'll never even come up, but if they aren't they're committing a grave offense against society as a whole, and shouldn't be allowed to limp away with whatever illicit evidence they've gathered while performing illegal acts.
Note that in the parent post I'm explicitly mentioning direct criminal action against the officer personally, not compensation claims against the police district; as far as I understand, fines are not an option for felonies in USA, and even the lightest possible 'guilty' sentence would automatically get such policemen out of their jobs after the first such act.