In the 1979 case, Ferri v. Ackerman, the United States Supreme Court determined that “independence” of appointed counsel to act as an adversary is an “indispensible element” of “effective representation.” Two years later, the Court determined in Polk County v. Dodson, that states have a “constitutional obligation to respect the professional independence of the public defenders whom it engages.” Observing that “a defense lawyer best serves the public not by acting on the State’s behalf or in concert with it, but rather by advancing the undivided interests of the client,” the Court concluded in Polk County that a “public defender is not amenable to administrative direction in the same sense as other state employees.”
This is confirmed in Strickland v. Washington. In that case, the Court states that “independence of counsel” is “constitutionally protected,” and that “[g]overnment violates the right to effective assistance when it interferes in certain ways with the ability of counsel to make independent decisions about how to conduct the defense.”
In the United States, there are two primary types of undue interference on the defense function: judicial interference and political interference. National standards suggest that the best way to protect defense counsel independence – either on the municipal, county or state-level – is by establishing an independent public defender commission.