For law enforcement agencies to get a pen register approved for surveillance, they must get a court order from a judge. According to 18 U.S.C. § 3123(a)(1), the "court shall enter an ex parte order authorizing the installation and use of a pen register or trap and trace device anywhere within the United States, if the court finds that the attorney for the Government has certified to the court that the information likely to be obtained by such installation and use is relevant to an ongoing criminal investigation". Thus, a government attorney only needs to certify that information will "likely" be obtained in relation to an 'ongoing criminal investigation'. This is the lowest requirement for receiving a court order under any of the ECPA's three titles. This is because in "Smith v. Maryland", the Supreme Court ruled that use of a pen register does not constitute a search. The ruling held that only the content of a conversation should receive full constitutional protection under the right to privacy; since pen registers do not intercept conversation, they do not pose as much threat to this right.