Retorsion
A phrase used in INTERNATIONAL LAW to describe retaliatory action taken by one foreign government against another for the stringent or harsh regulation or treatment of its citizens who are within the geographical boundaries of the foreign country.
The typical methods of retorsion are the use of comparably severe measures against citizens of the foreign nation found within the borders of the retaliating nation.
Additional topics
Law Library - American Law and Legal InformationFree Legal Encyclopedia: Reputation to Owen Josephus Roberts