Thoughts on qualified immunity
That's the court-created defense (nowhere to be found in statute or constitution) which consists of -- a governmental actor cannot be civilly sued unless his conduct was "clearly established" as unconstitutional at the time he acted.
I could accept that as a defense IF the same were applied to a non-governmental actor (like you or I) charged with a crime. Then it'd be simple fairness: someone ought not to be sanctioned for conduct that a reasonable person would not have thought illegal. Instead, of course, the default position in criminal law is "ignorance of the law is no excuse."
Today's Supreme Court ruling in Taylor v. Barkes illustrates another problem with the doctrine. If no suit can be filed until a right is clearly established, and the only way to establish it is by a definitive ruling, how can a right ever become clearly established outside of the realm of criminal procedure? (Inside that realm, a person can make and win a motion to suppress evidence, thereby establishing the right without having to win a civil suit). Here, the Court holds there was qualified immunity, since the right claimed was not established by Supreme Court precedent or by a "robust consensus" of Court of Appeals cases, suggesting that nothing less suffices.