Some interesting discussion about the Supreme Court of the United States' Hudson decision in the liberal legalist blogs, which split that court on liberal-conservative lines. Iocaste, currently a guest at Lawyers, Guns and Money, takes the liberal side. Publius says the conservative majority was right this time.
The case is ideal for law students because it arose out of the smallest possible (but conceded) violation of a constitutional right. Everyone agrees that the Fourth Amendment usually requires that the police knock at the door and wait "a reasonable amount of time" before they enter (Canadian law requires announcement as well, unless the police can justify otherwise ahead of time). This time, the police did announce themselves but waited what the state conceded to be not long enough.
They then found several rocks of crack and some guns. Should these be admitted?
There is no doubt that they would be admitted in Canada. Since the violation was small the issue really seems to be whether there should be a balancing test between the severity of the violation and the seriousness of an exclusionary remedy. I'm a big fan of balancing, so I'd say yes. Under s. 24(2) of the Charter, the Canadian courts do engage in balancing on exclusion applications, and have been known to say that they will let the evidence in "this time", but not if the same violation occurs in the future.
Unfortunately, since it is Scalia, he insists on a categorical rule -- no knocking violations can ever result in exclusion. That doesn't necessarily make sense, because some knock violations are worse than some infirmities of warrants. But, at least at the categorical level, he is prepared to balance, and Pith and Substance salutes him.