At the beginning of the twenty-first century two legal concepts linking citizen/ enemy status with criminal law have provoked heated discussion both in Europe and in the United States. The American concept, i.e., Enemy Combatants, has been basically developed by the U.S. Supreme Court and more recently by the Bush administration. The European term, Feindstrafrecht/Enemy Criminal Law, has been fundamentally coined and explained by leading German academic Professor Günther Jakobs. Though born and raised by different parents, the two concepts have numerous aspects in common, or at least this will be argued throughout the paper. The most important common ground is that both concepts, with similar terminology, try to address the problem of what to do with individuals who are viewed as sources of extreme dangerousness. Put differently, they both tackle the question of whether citizenship--in a broad sense--concedes certain rights but imposes a fundamental duty: to have a minimum of law-abiding behavior If the duty is not fulfilled, then the rights are not acknowledged and the individual is treated as an enemy, not as a citizen. The underlying reasoning oozes social contract theory. This is not by chance, as great philosophers (Rousseau, Fichte, Hobbes, Kant) have employed similar arguments that are briefly sketched in the essay. There are also references to the legal theory behind the scenes predicating that in order for legal constructions to exist (rights, the State), they need to be followed by most people. Hence such a duty to comply, in general terms, with the law is imposed upon all persons. If not, law would be just daydreaming. Strong and consistent as all these arguments sound, the basic problem with this type of reasoning is that it is hard for the legal system to follow without entering into self-contradiction. In this light, criticism will be brought by one of the most prominent social theories of the time, i.e., systems theory, arguing that law-abiding behavior is a precondition for legal institutions to exist, yes, but it cannot be secured by law itself. It is a precondition that has to be presupposed by the legal system. Moreover, using this kind of necessity rule, i.e., the State and the Law need to secure the preconditions of their own existence (self-preservation), entails a diabolic logic as it may lead to the destruction of the system itself. To this extent, self-preservation against external threats (terrorist attacks) and internal threats (curtailment of civil liberties) seems equally important. The essay finishes with some proposals for resolving this delicate matter, trying to reflect a keen sense of balance and forward-looking thinking. [ABSTRACT FROM AUTHOR]