“The U.S. could take the position that subjecting Ms. Knox to re-prosecution in Italy could violate her constitutional rights as a U.S. citizen,” Mr. Zagaris said.
“In circumstances where a requested person has been previously acquitted for the same act or offense in the requesting country, it has been held that there is no constitutional or statutory bar to the U.S. granting extradition. … It is an issue U.S. extradition treaties normally do not cover. Ordinarily, the secretary of state in his or her discretionary authority must deal with this issue.”
Mr. Kerry’s potential conundrum shines a light on the emerging era of “transnational law,” which pits the domestic laws of one country against the citizens of another. In this case, three countries are affected — the U.S., Britain and Italy.
Transnational law differs from international law, which applies equally to members of the United Nations and is enforced by impartial, international bodies such as the International Criminal Court and the International Court of Justice.
Denying an Italian request to extradite Ms. Knox for the murder of a British national could have diplomatic consequences with Italy and Britain.
“Extradition is a mutuality-reciprocal relationship, and Italy would not feel good about accusations concerning its criminal justice system,” Mr. Zagaris said.
If the U.S. denies an Italian extradition request but later needs to extradite a fugitive from Italy, authorities there could “return the favor” by denying the U.S. request, possibly turning Italy into a haven for organized crime syndicates there.
In a 2013 Wall Street Journal article, Harvard law professor Alan Dershowitz opined: “As national borders become more porous … the trend toward the transnational application of laws will become more pronounced. … By becoming an exchange student in Italy, Ms. Knox subjected herself to Italian law. By coming back to America, she received the protection of the American extradition process. As for how this will turn out, she is in uncharted territory.