It's always good to see Michael "No probable cause" Hayden posting. No, the 4th Amendment is not simply governed by the phrase "reasonable." Because it's nearly guaranteed that the government executing the search ALWAYS sees its actions as unquestionably reasonable. Michael Hayden himself argued with a journalist that the phrase "probable cause" did not appear in the 4th Amendment. He kept digging even after being taken to task, arguing, "If there's any amendment we know at the NSA, it's the Fourth!"