This is something that happens a lot in television and movies (Cop 1: "Did you hear screaming behind the door?" Cop 2: "No I....oh yeah, someone must be in DANGER!" Cops kick in door and see evidence for their case), but not so much in reality.

I too find it troubling that the Supreme Court upheld the government's position that it was a valid search.

I actually think the search was valid (and remember McGacken consented, which was a public-spirited action). What bothers me is that in establishing that a potentially serious crime had not taken place, a victimless one resulted in a pirson term. McGacken did the morally right thing in allowing the police officer to verify that nobody was in danger, and while I can't really fault the police officer for doing his job, I wish he had looked the other way.

What really bothers me about it is that I can't articulate a clear legal principle about when prima facie evidence of a crime should be thrown out for moral reasons. You could say that if you're investigating one crime then discovering another one incidentally shouldn't count, but what if the police officer had been investigating a report of illegal marijuana production and had discovered the rape in progress? Of course we'd want that to be prosecutable. We could wish that the war on drugs were over and nobody would be prosecuted for Marijuana, but I can think of other petty crimes that would substitute equally well, eg if McGacken was a petty thief or something. It's a really tricky case to me. I'm surprised nobody has examined it in a law review article.

It seems like we could establish some hierarchy (in fact, we already have one implicit in maximum or minimum sentence lengths, though I don't know if that is the right one to use). When an officer asks to engage in a search, he can then state "I am investigating X, we will ignore anything less serious."

If something is seen, it seems like it would be hard to prevent the officer from making a mental note to look into that guy later. We could grant immunity, but that could also get weird. I think just narrowly excluding the evidence uncovered in the search would still probably be an improvement, though (probably...).