You're getting a lot of huffy responses to this question, but it is an entirely legitimate one. In fact, many (maybe most?) western countries don't have the same exclusionary rules the US has. There are other remedies to police misconduct. If you were starting a nation from first principles, it's not an iron law of justice that your courts have that rule.

The reason we believe the exclusionary rule works so well is that it strikes directly at the incentive structure for the police. We don't have to convince evidence-gathering officers of their liability or assess liability up and down the chain of responsibilities on the prosecution's side; we just have to assess whether evidence was handled properly, and, if it wasn't, the prosecutors lose the evidence. The one simple rule neatly ensures that nobody --- in any role --- on the prosecution's side has any incentive to mishandle evidence (or coerce underlings or partner organizations to mishandle it).

But clearly the rule isn't a requirement. We don't generally believe, for instance, that Canada's criminal justice system is systemically corrupt, and they don't have a hard-and-fast exclusion rule.