(f) Emergency orders
Notwithstanding any other provision of this subchapter, when the Attorney General reasonably determines that—
(1) an emergency situation exists with respect to the employment of electronic surveillance to obtain foreign intelligence information before an order authorizing such surveillance can with due diligence be obtained; and
(2) the factual basis for issuance of an order under this subchapter to approve such surveillance exists;
he may authorize the emergency employment of electronic surveillance if a judge having jurisdiction under section 1803 of this title is informed by the Attorney General or his designee at the time of such authorization that the decision has been made to employ emergency electronic surveillance and if an application in accordance with this subchapter is made to that judge as soon as practicable, but not more than 72 hours after the Attorney General authorizes such surveillance.
http://www.law.cornell.edu/uscode/html/uscode50/usc_sec_50_00001805----000-.htmlRoving wiretaps were specifically invented to counter the changing phones technique.
"To "rove" means to wander from place to place, with no particular destination. A "roving wiretap" is a tap on any telephone that a suspect uses, roving from one telephone to another, with no particular locational target. The United States Federal Bureau of Investigation is now authorized to engage in roving wiretaps without having to get approval by a court."
http://www.progress.org/archive/fold79.htmAs you can see, the information is out there, if you want it. The people who don't have the facts are the Bush apologists, who are just saying whatever they think will help him, regardless of whether its true. DU, as you know, is one of the best places to find the facts.