Prosecution and defense
When ordinary crimes cross the threshold and become international crimes, important consequences ensue. Most significantly, general legal rules on the exercise of jurisdiction no longer apply. Under international law, a national criminal-justice system may prosecute crimes committed within the state’s own territory or by its nationals but not, as a general rule, crimes committed outside its borders by nonnationals. This rule, however, has been relaxed in the case of war crimes, crimes against humanity, and genocide. Under what is known as universal jurisdiction, national courts may prosecute these offenses no matter where or by whom they are committed. Indeed, in the 1990s Belgium adopted controversial legislation that granted its courts the authority to try anyone—even the leaders of other countries—for such offenses. In 2001 the International Court of Justice ruled that the Belgian legislation was invalid because it wrongly assumed that Belgian courts can try foreign heads of state or other senior officials while they are still in office. Following the judgment, and under pressure from states that threatened to prohibit official travel to Belgium, the Belgian government modified the legislation. In the case of grave breaches of the Geneva Conventions and the crime of torture, international treaties make prosecution not only a right but a duty. Under the principle known as aut dedere aut judicare (Latin: “either adjudicate or extradite”), national governments must either try offenders or extradite them to a country that is prepared to do so. The “try or extradite” principle can also be found in treaties dealing with terrorism, counterfeiting, and the theft of nuclear materials.
Special rules apply to the arguments an accused may raise in defense of his actions. Although a head of state may benefit from immunity under national law, he cannot invoke this defense in the case of war crimes, crimes against humanity, and genocide. He may, however, plead immunity from prosecution by other states for crimes committed while he was in office, as long as they were not committed in a private context. Nevertheless, heads of state have no such immunity before international courts or tribunals. In addition, statutory limitations, a common bar to prosecution many years after a crime has taken place in many national legal systems, are excluded by both treaty and customary law for war crimes, crimes against humanity, and genocide.
Individuals also may not argue in their defense that they were acting under the orders of a superior, though this is permitted for soldiers and officers of the peace in most national legal systems. Although subordinates cannot be exonerated in such circumstances, international criminal law focuses its attention primarily on commanders. Those with superior authority, be they military or civilian, may be found guilty of war crimes, crimes against humanity, and genocide when they are committed by those under their command, even when there is no evidence that they actually ordered the commission of the crime.
International courts and tribunals
World Wars I and II
In 1919 the Treaty of Versailles contemplated the establishment of an international court to prosecute German Emperor William II “for a supreme offense against international morality and the sanctity of treaties.” The court was never set up, however, because William obtained asylum in a neutral country, the Netherlands. The victorious allies at the close of World War II were more successful, establishing by treaty the tribunal at Nürnberg that judged “the major war criminals of the European Axis.” In all, some 22 leading Nazis were tried by a court composed of eight judges (four judges rendered the verdicts, and four served as alternates), two each from the United States, the United Kingdom, France, and the Soviet Union.
Critics of the Nürnberg trials, and of a similar prosecution held in Tokyo, have viewed them as “victor’s justice,” particularly because the tribunals never considered war crimes committed by their own soldiers, though in at least one case, concerning submarine warfare, the argument that illegal acts had also been committed by the other side was accepted as a defense. Despite such flaws, the tribunals represented a great achievement for those who desired an international system that would prosecute heinous offenses committed during war.