456 Between Yesterday and Tomorrow (1914– )cerned over incompatibility between traditional liberal values and the ur-
gent need to protect the environment. His principal concern was over-
population. Part of his proposed solution was drastic: bringing an end to
what Hardin called “our present policy of laissez- faire in reproduction.”
Th e principle of “freedom to breed,” in combination with the belief that all
persons have “an equal right to the commons,” was seen as producing a
global tragedy. Hardin was expressly critical of the Universal Declaration
of Human Rights for exacerbating the situation by its assertion of a funda-
mental right to marry and found a family. “If we love the truth,” he warned,
“we must openly deny the validity of the Universal Declaration of Human
Rights.”
Nor, maintained Hardin, would it suffi ce simply to urge individuals to
exercise restraint and responsibility. Some form of compulsion will be nec-
essary. “Th e only way we can preserve and nurture other and more precious
freedoms is by relinquishing the freedom to breed, and that very soon.” In
support of that thesis, the noted economist Kenneth Boulding proposed (ap-
parently in all seriousness) that human breeding be licensed, by means of
the issuance of tradable permits to have children. With only a fi xed number
of permits issued, market forces would channel reproduction activity in the
direction of those willing or able to acquire the necessary licenses.
Th e way to resolve such clashes of rights and values, in the opinion of
constitutionalists, is to devise some kind of “master system” of norms.
Where traditional international law adjudicated disputes between states, the
constitutionalist version would adjudicate disputes between rival subsys-
tems or rival sets of rules. Th e quest for a master system of norms has been
in some ways reminiscent of the search of Kelsen and the Vienna School for
a basic norm on which to ground the whole of international law. But where
Kelsen had posited the existence of a single basic norm, which was inevitably
very general in nature, the constitutionalists envisage a whole system of
rules. Moreover, these rules are not seen as abstract and formal, in the man-
ner of Kelsen’s normative system, but instead as fairly specifi c, concrete, and
substantive.
It has been envisaged that constitutionalism in action would function in
practice somewhat along the lines of the American and German federal
models. An overarching rule of law would operate in a continuous fashion
to resolve clashes of jurisdiction and confl icts between substantive norms,