(a) In General.âExcept as provided in subsection (b), this title and the amendments made by this title (other than sections 203(a) 203(c), 205, 208, 210, 211, 213, 216, 219, 221, and 222, and the amendments made by those sections) shall cease to have effect on December 31, 2005. (b) Exceptions.âWith respect to any particular foreign intelligence investigation that began before the date on which the provisions referred to in subsection (a) cease to have effect, or with respect to any particular offense or potential offense that began or occurred before the date on which such provisions cease to have effect, such provisions shall continue in effect. P.L. 107-56 , Â§224, 18 U.S.C. 2510 note (emphasis added). (a) In General.âSection 101(b)(1) of the Foreign Intelligence Surveillance Act of 1978 (50 U.S.C. 180(b)(1) is amended by adding at the end the following new subparagraph: "(C) engages in international terrorism or activities in preparation therefore; or". (b) Sunset.âThe amendment made by subsection (a) shall be subject to the sunset provision in section 224 of P.L. 107-56 (115 Stat. 295), including the exception provided in subsection (b) of such section 224. P.L. 108-458 , Â§6001, 118 Stat. 3742 (2004). Section 224(a) of the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism (USA PATRIOT ACT) Act of 2001 (18 U.S.C. 510 note) is amended by striking "December 31, 2005" and inserting "February 3, 2006." P.L. 109-160 , 119 Stat. _____(2005). Section 224(a) of the Uniting and Strengthening American by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism (USA PATRIOT ACT) Act of 2001 ( P.L. 107-56 ; 115 Stat. 295) is amended by striking "February 3, 2006" and inserting "March 10, 2006." H.R. 4659 , P.L. 109-___, 120 Stat. (2006). Subsection 224(a) of the USA PATRIOT Act (the act) indicates that various sections in Title II of the act are to remain in effect only until March 10, 2006. Subsection 224(b) creates two exceptions for matters that straddle the termination date, one for foreign intelligence investigations and the other for criminal cases. Even a quick reading of section 224 raises a number of questions. What is the substance of the temporary sections that disappear on March 10, 2006? What is the breath of the subsection 224(b) exceptions? What is the fate and impact of amendments to the expiring sections or to related provisions of law, enacted after passage of the act but before March 10, 2006? What is the substance of the sections in Title II that continue on unimpaired by virtue of their inclusion in the "other-than" list of the subsection 224(a)? These questions are among those likely to be asked as twilight approaches. The 9/11 Commission noted the coming sunset, and expressed the belief that as a general matter, "[b]ecause of the concerns regarding the shifting balance of power to the government . . .a full and informed debate on the Patriot Act would be healthy," 9/11 Commission Report , 394 (2004). The expiring sections deal with the power of federal authorities to conduct searches and seizures, generally searches and seizures relating to communications. In most instances, they allow authorities to move more quickly; they reduce the required layers of administrative and judicial approval; they permit searches and seizures of a wider range of targets thus making these tools available earlier in an investigation; and they allow authorities to coordinate their activities. In doing so, they make it more likely that terrorism and crime will be prevented and that terrorists and criminals will be caught and punished. They accomplish these things, however, by easing or removing safeguards designed to protect individual privacy and to prevent government abuse. And so, they increase the risk that government authority will be abused and that the privacy of those who are neither terrorists nor criminals will be invaded. The debate over sunset is a debate of where the balance should be struck. To further complicate the debate, in some instances the expiring sections curtail rather than expand governmental authority; bolster rather than erode the safeguards against governmental overreaching or abuse of authority. The USA PATRIOT Act sections were originally set to sunset on December 31, 2005. By then, both Houses had passed legislation that amended and extended the expiring sections ( H.R. 3199 ) and a conference report resolving their differences had been issued, H.Rept. 109-433 (2005). In order to provider further time for consideration, the expiration date has been extended twice, first until February 3, 2006, P.L. 109-160 (2006), and more recently until March 10, 2006, H.R. 4659 , P.L. 109-____ (2006). Subject to the exceptions of subsection 224(b), the new sections of law and the amendments to existing law, created by the sections of the act that expire on March 10, 2006, will cease to exist after that date. The same is true for any subsequent amendments to the expiring sections. They expire along with their hosts. Pre-existing provisions of law, repealed or amended by the expiring sections, will be revived automatically, unless they themselves have been repealed or amended by intervening legislation (as several have). The impact of subsection 224(b) is somewhat more difficult to discern. It provides two standards: one with respect to "any particular foreign intelligence investigations that began" before sunset and a second with respect to "any particular offense or potential offense that began or occurred" before sunset, P.L. 107-56 , Â§224, 18 U.S.C. 2510 note. The first seems fairly straightforward. The authority granted by an expiring provision of the act may be exercised after sunset or may continue to be exercised after sunset, with respect to any foreign intelligence investigation initiated before sunset. The second comes with questions. What is a "potential offense"? Does the phrase refer to pre-sunset circumstances whose criminality is determined in a post-sunset investigation? Or does the phrase also include post-crimes that evolved out of pre-sunset circumstances which themselves constituted neither crimes nor elements of a crime? As a general rule, when Congress uses ordinary words, it is presumed to have intended them to have their commonly understood meaning. The word "potential" usually contemplates the incomplete, the unfulfilled, the undeveloped, or the unawakened possibility, rather than the suspected or uncertain possibility. That might suggest the term was intended at least in part to apply to post-sunset crimes that grow out pre-sunset circumstances. Although hardly a term of art, earlier federal courts have used the term to describe possible past offenses in some cases, and to describe possible future offenses in others. Congress in subsection 224(b), however, is not referring to all "potential offenses," but only to those "that began or occurred" before sunset. Offenses occurring entirely after sunset cannot be said to have begun or occurred beforehand. Thus, although it is scarcely beyond debate, Congress appears to have added the term "potential offense" out of an abundance of caution lest the exception be read to extend only to investigations of conduct whose criminality was known prior to sunset but not of pre-sunset conduct whose innocence or criminality was only ultimately determined after sunset. The expiring law enforcement sections of Title II of the USA PATRIOT Act involve three communications-related aspects of federal law: wiretapping; stored electronic communications and communication transaction records; and pen registers and trap and trace devices. Federal law prohibits the interception of telephone, face to face, and electronic communications (wiretapping), subject to certain exceptions including a procedure for judicially supervised law enforcement interceptions, 18 U.S.C. 2510-2520 (Title III). With the approval of senior Justice Department officials, federal law enforcement authorities may apply for a court order approving the use of wiretapping in connection with the investigation of certain serious federal crimes, 18 U.S.C. 2516, 2517, 2518. The orders must be narrowly drawn, of short duration, and based upon probable cause to believe that they will generate evidence relating to the predicate offenses under investigation, id. When the orders expire, those whose communications have been intercepted must be notified, 18 U.S.C. 2518. The procedure for law enforcement access to the content of wire and electronic communications stored with communications providers and to provider transaction records is somewhat less demanding, although it generally requires a court order, warrant, or subpoena, 18 U.S.C. 2701-2702. Pen registers and trap and trace devices surreptitiously capture the identity of the sender and recipient of communications. The procedure for a court order approving law enforcement installation and use of a pen register or a trap and trace device is less demanding still, 18 U.S.C. 3121-3127. Federal courts may authorize wiretappingâthe interception of wire, oral or electronic communicationsâfor law enforcement purposes in connection with the investigation of one or more specifically designated, serious federal crimes (predicate offenses), 18 U.S.C. 2516. Sections 201 and 202 temporarily add crimes to this predicate offense list. Section 202 places felonious violations of 18 U.S.C.