&gt;Alleged pedophiles, terrorists and drug dealers have the full panoply of rights available...<p>For starters, lets throw <i>right to privacy</i> out the window, from the US perspective what we are talking about is 4th Amendment &quot;right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures.&quot;<p>&gt;Only after THAT hurdle is cleared may the rights of the alleged criminal be intruded upon by the state...<p>No.  In many instances police are not limited to obtaining a warrant&#x2F;judicial oversight before conducting searches and seizures (including communications).  Just a few examples: (a) if an officer conducts a lawful traffic stop, and smells marijuana (plain-view&#x2F;plain-smell doctrine) the officer can lawfully search your person and the vehicle,seizing any evidence of a crime, even if unrelated to marijuana; or (b) subsequent to a DUI arrest, an officer can impound the vehicle and conduct a search&#x2F;inventory of the vehicle and seize any evidence of a crime (even unrelated to the DUI).  These are some of the many lawful Government searches and seizures without prior judicial approval.<p>&gt;At least in America, a judge cannot issue a warrant for the wiretaps you described on the mere accusation that &quot;so and so is a {pedophile,terrorist,drug dealer}.&quot;<p>A judge certainly can issue a warrant based on accusation as long as the judge makes a finding there is probable cause.  In fact an officer can obtain a warrant from a Judge based on an anonymous tip, or what would be called hearsay evidence which would be inadmissible in an actual trial.