"Europe's Runaway Prosecutions"

An Italian Court is preparing to prosecute CIA agents for their alleged participation in the kidnapping and rendition of a Muslim cleric. The cleric was sent to Egypt where he claims he was tortured. Writing in today's Washington Post, David Rivkin and Lee Casey argue that this prosecution is part of a disturbing trend: "Overseas opponents of American foreign policy are increasingly turning to judicial proceedings against individual American officials as a means of reformulating or frustrating U.S. aims, and action to arrest this development is needed."

Rivkin and Casey argue that "extraordinary rendition" is perfectly legal, but can and should be ended because it is unnecessary and is fervently opposed by European nations. This does not justify the Italian prosecution, however. Indeed, they suggest that the CIA agents should be immune to prosecution if, as reported, Italian officials were aware of their activities. They conclude with a particularly provocative claim:

Congress should make it a crime to initiate or maintain a prosecution against American officials if the proceeding itself otherwise violates accepted international legal norms. Thus, in instances where there is a clear case of immunity, U.S. prosecutors could answer proceedings such as the Italian indictments with criminal proceedings in U.S. courts. By responding in kind, even if few overreaching foreign officials are ever actually tried, such a law would create a powerful disincentive for these kinds of legal antics.
This would seem to me to be an unprecedented step -- and potentially at odds with Rivkin & Casey's opposition to the criminalization of foreign conduct. Am I missing something? Is there any precedent for what they propose?