In the US system of government, checks and balances are essential to counter overreaching and abuse from any single branch. If no such checks exist against unjust prosecutions by law enforcement (the executive branch), then by default, either the judiciary or legislative branch must be at fault, or both.

In this case, it's clearly BOTH the US legislature and US courts have been remiss. Both should step in and outlaw any private funding of public law enforcement, as well as require ALL public court prosecutions to abide by the same burden of proof and evidence required of any gov't/DA-led investigation.

To allow the routine "negotiation of guilt" between prosecutors and the prosecuted to circumvent due process certainly is a violation of the Constitution -- something all three branches share culpability for allowing.