If they could trust the courts to accurately define reasonable/unreasonable, then why would they have any warrant requirement?
From Vigilantes with a Badge: The War Against the American People
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As journalist Herman Schwartz observed, The Fourth Amendment was designed to stand between us and arbitrary governmental authority. For all practical purposes, that shield has been shattered, leaving our liberty and personal integrity subject to the whim of every cop on the beat, trooper on the highway and jail official.
I don’t claim that the Supremes have properly decided the bounds of “reasonable” searches, only that the Constitution gave them the authority to set those bounds.