Third, it is impossible to conceive of prosecutors as 'quasi-judicial officers.' They are unequivocally officers of the executive. In fact, as far as the bill of rights and individual liberties are concerned, prosecutors are the bared teeth and most naked expression of the power of the executive.
And yet, the SCOTUS in Imbler v. Pachtman, 424 U.S. 409 (1976) actually did describe prosecutors in exactly those terms: quasi-judicial officers. Check out some of Justice Powell's language in this 9-0 decision:
These courts sometimes have described the prosecutor's immunity as a form of "quasi-judicial" immunity, and referred to it as derivative of the immunity of judges ...
Petitioner ... contends that ['the "quasi-judicial" characterization'] illustrates a fundamental illogic in according absolute immunity to a prosecutor. He argues that the prosecutor, as a member of the executive branch, cannot claim the immunity reserved for the judiciary, but only a qualified immunity akin to that accorded other executive officials in this Court's previous cases.
Petitioner takes an overly simplistic approach to the issue of prosecutorial liability.
It is the functional comparability of [a prosecutor's] judgments to those of the judge that has resulted in both grand jurors and prosecutors being referred to as "quasi-judicial" officers, and their immunities being termed "quasi-judicial" as well.
Without having at that time read the case, I responded to mistcr by surmizing that the characterization of prosecutors as 'quasi-judicial' derived from the notion of 'officers of the court.' I appear to have been correct, because Justice Powell also wrote this:
At some point, and with respect to some decisions, the prosecutor no doubt functions as an administrator, rather than as an officer of the court. Drawing a proper line between these functions may present difficult questions, but this case does not require us to anticipate them.
Let's see. Drawing a proper line between a prosecutor's executive functions ('administrative') and his function as an 'officer of the court' 'may present difficult questions.' No kidding? But rather than anticipating those difficult questions let's just go ahead and legislate from the bench: prosecutors get absolute immunity. After, it works for us judges, so why not for prosecutors--what could possibly go wrong? Of course, the facts of the case itself illustrated what could go wrong--the prosecutor had "knowingly used false testimony and suppressed material evidence at ... trial." And for that he should have absolute immunity ... just because? Go figure. You'd have to be a SCOTUS justice to understand the subtlety of that one.