Key to any successful attempt to combat international terrorism is the elimination of sanctuary and safe-haven for terrorists. The United States has pressed consistently for international agreements – the anti-hijacking conventions and the Internationally Protected Persons Convention being examples – requiring States either to prosecute or extradite international terrorists found within their borders. Because its efforts to establish a "basic extradite-or-prosecute obligation" have not met with general success, the U.S. has had to consider, among other alternatives, various unilateral responses to help curb terrorist activities. One obvious response, drawing upon a wealth of domestic precedents, involves the possible invocation of economic sanctions.
Since the enactment in 1962 of the Hickenlooper Amendment, which proscribed the nationalization of U.S.-owned property without the payment of prompt, adequate, and effective compensation, the U.S. has threatened recipients of economic or military aid with its termination if they engaged in various acts which conflicted with major U.S. foreign policy objectives.
No one disputes that State terrorism is a serious problem and that it certainly deserves more adequate scrutiny and condemnation than it has received to date. The fact is, though, that there already exists a large body of conventional international law regulating State terrorism in the armed conflict context. Additionally, there is a substantial and developing body of customary international law governing the responsibility of States for terrorist activities which they either initially sponsor or subsequently assist in accessory-after-the fact fashion. Moreover, another provision in the Foreign Assistance Act of 1961, as amended, requires the termination of U.S. aid to States that utilize terror against their own citizens, the same sanction device found in the terrorism amendment. Finally, there is no dispute that the underlying causes of terrorism should be studied and then eliminated. The recognition of this fact, however, does not mean that one should stand idly by while terrorist outrages continue. No one today would contend seriously that the U.S. should limit itself to studying the causes and alleviating the impact of racism, all the time foregoing the opportunity to pass laws against racial discrimination. The same reasoning applies in the terrorism field.
Thomas E. Carbonneau and Richard Lillich, The 1976 Terrorism Amendment to the Foreign Assistance Act of 1961, 11 J. Int'l L. & Econ. 223 (1977).