For people who care about civil liberties, it was definitely not a good thing when the Roberts Court decided to hear an exclusionary rule case this term. As Adam notes below, the Court's Wednesday decision in Herring v. U.S. confirmed these fears, holding that evidence obtained after an illegal search did not have to be excluded under the circumstances. (Police conducted a search based on an expired warrant, which appeared to still be valid because of their own negligence.) For reasons I went into in the post linked above, I strongly disagree with the Court's judgment -- the gutting of the exclusionary rule reduces incentives for state officials to comply with constitutional commands.
And it's even worse than it might have been. Tom Goldstein notes that the case goes well beyond previous exclusionary rule exceptions:
The opinion has nothing to do with the fact that the error here is one of record keeping. It applies fully to negligence by police officers in their day-to-day determination whether there is probable cause to conduct a search. If the officer makes an objectively reasonable mistake - i.e., he is merely negligent - the exclusionary rule does not apply to whatever evidence he finds. Put another way, the Supreme Court today extended the good faith exception to ordinary police conduct.
As Breyer noted in his dissent, the Court had previously confined the "good faith" exception to cases where negligence by other actors led police to conduct an illegal search. Contra Breyer, this never made much sense -- it's far from clear why the exclusionary rule should be addressed only to police misconduct rather than illegal actions by all state actors -- so the Court refusing to confine the exception to non-police actors has its own grim logic. The fact that the Court permitted an exception in a run-of-the-mill drug possession and gun case as opposed to a serious violent crime makes clear that the cost-benefit analysis will be done with a 2-ton anvil on the state's side. There's no serious weighing of costs and benefits being done here at all.
Finally, it should be noted that once again the purported "minimalism" of Roberts is a complete farce. Roberts and Alito aren't substantively "minimalist" even if they abjure grand theory, and this will be far from the last 5-4 Roberts decision that (however the opinion chooses to characterize the precedents) revises a substantial body of law in an inevitably reactionary direction.