Obstruction of justice is the frustration of governmental purposes by violence, corruption, destruction of evidence, or deceit. It is a federal crime. In fact, federal obstruction of justice laws are legion; too many for even passing reference to all of them in a single report. This is a brief description of those that outlaw interference with congressional activities. The general federal obstruction of justice provisions are six: 18 U.S.C. 1512 (tampering with federal witnesses), 1513 (retaliating against federal witnesses), 1503 (obstruction of pending federal court proceedings), 1505 (obstruction of pending congressional or federal administrative proceedings), 371 (conspiracy), and contempt. All but §1503 apply to congressional activities. In addition to these, there are a host of other statutes that penalize obstruction by violence, corruption, destruction of evidence, or deceit. Section 1512 applies to the obstruction of federal proceedings—congressional, judicial, or executive. It consists of four somewhat overlapping crimes: use of force or the threat of the use of force to prevent the production of evidence (18 U.S.C. 1512(a)); use of deception or corruption or intimidation to prevent the production of evidence (18 U.S.C. 1512(b)); destruction or concealment of evidence or attempts to do so (18 U.S.C. 1512(c)); and witness harassment to prevent the production of evidence (18 U.S.C. 1512(d)). The offenses have similar, but not identical, objectives and distinctive elements of knowledge and intent. Section 1512 also contains free standing provisions that apply to one or more of the offenses within the section. These deal with: affirmative defenses (18 U.S.C. 1512(e)); jurisdictional issues (18 U.S.C. 1512(f),(g),(h)); venue (18 U.S.C. 1512(i)); sentencing (18 U.S.C. 1512(j)); and conspiracy (18 U.S.C. 1512(k)). Subsection 1512(a) has slightly different elements depending upon whether the offense involves a killing or attempted killing—18 U.S.C. 1512(a)(1), or some other use of physical force or a threat—18 U.S.C. 1512(a)(2). In essence, they condemn the use of violence to prevent a witness from testifying or producing evidence for an investigation and set their penalties according to whether the obstructive violence used is a homicide, an assault or a threat. In more exact terms, they declare: Unless countermanded by subsection 1512(j), subsection 1512(a)(3) provides the sanctions for both subsection 1512(a)(1) and (a)(2). Homicide is punished as provided in 18 U.S.C. 1111 and 1112, that is, murder in the first degree is punishable by death or imprisonment for life; murder in the second degree is punishable by imprisonment for any term of years or for life; voluntary manslaughter is punishable by imprisonment for not more than 15 years and involuntary manslaughter by imprisonment for not more than 8 years. Attempted murder, assault, and attempted assault are punishable by imprisonment for not more than 30 years; and a threat to assault punishable by imprisonment for not more than 20 years. Subsection 1512(j) provides that the maximum term of imprisonment for subsection 1512(a) offenses may be increased to match the maximum term of any offense involved in an obstructed criminal trial. "To establish a crime under the [disclosure to a] 'law enforcement officer' section of the Act, the government must prove that (1) the defendant killed or attempted to kill a person; (2) the defendant was motivated by a desire to prevent the communication between any person and law enforcement authorities concerning the commission or possible commission of an offense; (3) the offense was actually a federal offense; and (4) the defendant believed that the person in (2) above might communicate with the federal authorities." There are two statutory defenses to charges under §1512. One covers legitimate legal advice and related services, 18 U.S.C. 1515(c), and is intended for use in connection with the corrupt persuasion offenses proscribed elsewhere in §1512 rather than the violence offenses of subsection 1512(a). The other statutory defense is found in subsection 1512(e) and creates an affirmative defense when an individual engages only in conduct that is lawful in order to induce another to testify truthfully. The defense would appear to be of limited use in the face of a charge of the obstructing use or threat of physical force in violation of subsection 1512(a). Subsections 1512(f) and 1512(g) seek to foreclose a cramped construction of the various offenses proscribed in §1512. Subsection 1512(f) declares that the evidence that is the object of the obstruction need not be admissible and that the obstructed proceedings need not be either pending or imminent. Whether the defendant's misconduct must be shown to have been taken in anticipation of such proceedings is more difficult question. The Supreme Court rejected the contention that language like that found in subsection 1512(f) (making §1512 applicable to obstructions committed before any official proceedings were convened) absolved the government of having to prove that the obstruction was committed with an eye to possible official proceedings. That case, the Arthur Andersen case, however, involved the construction of subsection 1512(b) which requires that the defendant be shown to have "knowingly" engaged in the obstructing conduct. Subsection 1512(a) has no such explicit "knowing" element. Yet, the government must still show that the offender's violent act was committed with the intent to prevent testimony or the disclosure of information to law enforcement authorities. By virtue of subsection 1512(g), the government need not prove that a §1512 offender knew of the federal status of the obstructed proceeding or investigation. Thus, for instance, to prove an information obstruction offense, it need show no more than that the offender intended to prevent the flow of information to law enforcement authorities concerning a federal crime ; it need not demonstrate that the offender intended to prevent the disclosures to federal authorities . As a consequence of subsection 1512(h), murder, attempted murder, or the use or threat of physical force—committed overseas to prevent the appearance or testimony of a witness or the production of evidence in federal proceedings in this country or to prevent a witness from informing authorities of the commission of a federal offense or a federal parole, probation, supervised release violation—is a federal crime outlawed in subsection 1512(a) that may be prosecuted in this country. As a general rule, the courts will assume that Congress intends a statute to apply only within the United States and to be applied consistent with the principles of international law—unless a contrary intent is obvious. Subsection 1512(h) supplies the obvious contrary intent. Since a contrary intent may be shown from the nature of the offense, the result would likely be the same in the absence of subsection 1512(h). In the case of an overseas obstruction of federal proceedings, the courts could be expected to discern a congressional intent to confer extraterritorial jurisdiction and find such an application compatible with the principles of international law. The existence of extraterritorial jurisdiction is one thing; the exercise of such jurisdiction is another. Federal investigation and prosecution of any crime committed overseas generally presents a wide range of diplomatic, legal and practical challenges. Subsection 1512(i) states that violations of §1512 or §1503 may be prosecuted in any district where the obstruction occurs or where the obstructed proceeding occurs or is to occur. In the case of obstructions committed in this country, the Constitution may limit the trial in the district of the obstructed proceedings to instances when a conduct element of the obstruction has occurred there. Subsection 1512(k) makes conspiracy to violate §1512 a separate offense subject to the same penalties as the underlying offense. The section serves as an alternative to a prosecution under 18 U.S.C. 371 that outlaws conspiracy to violate any federal criminal statute. Section 371 is punishable by imprisonment for not more than five years and conviction requires the government to prove the commission of an overt act in furtherance of the scheme by one of the conspirators. Subsection 1512(k) has no specific overt act element, and the courts have generally declined to imply one under such circumstances. Regardless of which section is invoked, conspirators are criminally liable as a general rule under the Pinkerton doctrine for any crime committed in the foreseeable furtherance of the conspiracy. Accomplices to a violation of subsection 1512(a) may incur criminal liability by operation of 18 U.S.C. 2, 3, 4, or 373 as well. Section 2 treats accomplices before the fact as principals. That is, it declares that those who command, procure or aid and abet in the commission of a federal crime by another, are to be sentenced as if they committed the offense themselves. As a general rule, "[i]n order to aid and abet another to commit a crime it is necessary that a defendant in some sort associate himself with the venture, that he participate in it as in something he wishes to bring about, [and] that he seek by his action to make it succeed." It is also necessary to prove that someone else committed the underlying offense. Section 3 outlaws acting as an accessory after the fact, which occurs when "one knowing that an offense has been committed, receives, relieves, comforts or assists the offender in order to hinder his or her apprehension, trial, or punishment." Prosecution requires the commission of an underlying federal crime by someone else.