50 U.S.C. § 1843

(a) Requirements for authorization Notwithstanding any other provision of this subchapter, when the Attorney General makes a determination described in subsection (b), the Attorney General may authorize the installation and use of a pen register or trap and trace device on an emergency basis to gather foreign intelligence information not concerning a United States person or information to protect against international terrorism or clandestine intelligence activities, provided that such investigation of a United States person is not conducted solely upon the basis of activities protected by the first amendment to the Constitution if— (1) a judge referred to in section 1842(b) 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 install and use the pen register or trap and trace device, as the case may be, on an emergency basis; and (2) an application in accordance with section 1842 of this title is made to such judge as soon as practicable, but not more than 7 days, after the Attorney General authorizes the installation and use of the pen register or trap and trace device, as the case may be, under this section. (b) Determination of emergency and factual basis A determination under this subsection is a reasonable determination by the Attorney General that— (1) an emergency requires the installation and use of a pen register or trap and trace device to obtain foreign intelligence information not concerning a United States person or information to protect against international terrorism or clandestine intelligence activities, provided that such investigation of a United States person is not conducted solely upon the basis of activities protected by the first amendment to the Constitution before an order authorizing the installation and use of the pen register or trap and trace device, as the case may be, can with due diligence be obtained under section 1842 of this title ; and (2) the factual basis for issuance of an order under such section 1842 of this title to approve the installation and use of the pen register or trap and trace device, as the case may be, exists. (c) Effect of absence of order (1) In the absence of an order applied for under subsection (a)(2) approving the installation and use of a pen register or trap and trace device authorized under this section, the installation and use of the pen register or trap and trace device, as the case may be, shall terminate at the earlier of— (A) when the information sought is obtained; (B) when the application for the order is denied under section 1842 of this title ; or (C) 7 days after the time of the authorization by the Attorney General. (2) In the event that an application for an order applied for under subsection (a)(2) is denied, or in any other case where the installation and use of a pen register or trap and trace device under this section is terminated and no order under section 1842 of this title is issued approving the installation and use of the pen register or trap and trace device, as the case may be, no information obtained or evidence derived from the use of the pen register or trap and trace device, as the case may be, shall be received in evidence or otherwise disclosed in any trial, hearing, or other proceeding in or before any court, grand jury, department, office, agency, regulatory body, legislative committee, or other authority of the United States, a State, or political subdivision thereof, and no information concerning any United States person acquired from the use of the pen register or trap and trace device, as the case may be, shall subsequently be used or disclosed in any other manner by Federal officers or employees without the consent of such person, except with the approval of the Attorney General if the information indicates a threat of death or serious bodily harm to any person. (3) A denial of the application made under subsection (a)(2) may be reviewed as provided in section 1803 of this title . (d) Privacy procedures Information collected through the use of a pen register or trap and trace device installed under this section shall be subject to the policies and procedures required under section 1842(h) of this title .