Treaty
‘Pacta serva sunt’—promises must be kept to—is one of the oldest maxims,
perhaps the very corner stone, ofinternational law, and is what underlies the
significance of the idea of a treaty in both public international law and the
academic study of international relations. A treaty is a formal agreement
between two or more states or other accepted international actors. It is
important that the actors be recognized by international law before an
agreement between them can be seen as a treaty, because treaties both depend
on international law for their validity and at the same time serve to develop
international law further. Thus a government might, to get out of a crisis, sign
an agreement with a terrorist group to release hostages, but that group could
not rely on the agreement in international law arbitration, or if the treaty were
upheld, the effect would be to transform the terrorists from an illegal band into
a legitimate state actor.
Essentially treaties can be either bilateral or multilateral. A bilateral treaty is
like a private contract in civil law—merely a negotiated interest between two
actors who have struck a bargain that both think is in their best interest. More
important and theoretically interesting are multilateral treaties, agreements
between several countries to act towards each other in particular ways, or to set
up international mechanisms and institutions to achieve goals co-operatively.
These types of treaties can be essentially negative, a multilateral arms control
treaty, for example, restricting or banning nuclear testing. Positive treaties, the
best single example being the Treaty of Rome (seeEuropean Union), can
create complex webs of rights and duties and set up supranational institutions
with their own legitimacy which may even transcend, intentionally or other-
wise, the legitimacy of those who sign the treaty in the first place.
Treaties are themselves, as noted above, sources of international law—not
only because they set out rules binding the signatories, but because interna-
tional law works in part by generalizing principles from specifics. Thus, a well
established treaty which, for instance, establishes territorial limits on national
waters between its signatories may be used as a form of precedent to bind other
countries that have never negotiated such an agreement. It is important to see
that treaties are creatures of international, rather than domestic, law: while
treaties are binding between the states that sign them, they may have no legal
impact within those states. It is a matter that differs across national legal cultures
as to whether a citizen inside a state may claim that his state is bound by
something in a treaty it has signed. There are numerous other words used to
describe international agreements; about the only thing that makes treaties
stand out is that they usually require ratification within each signing country by
the country’s constitutional mechanisms. Thus, for example, the US President
cannot make a treaty valid by signing it—it requires ratification by the Senate as
Treaty