doctrine fairly deduced, by correct reasoning, from
the rights and duties of nations, and the nature of moral obligation,
may be said to exist in the Law of Nations. Those rights, duties, and
that moral obligation, are to be ascertained from the enunciation of
them in past times, unless they have been relaxed, waived, or altered
by universal modern opinion.

We may regard, then, the Law of Nations to be a system of political
ethics; not reduced to a written code, but to be sought for, (not
founded,) in the elementary writings of publicists, judicial
precedents, and general usage and practice; but _continually_ open to
change and improvement; as the views of men in general, change or
improve, with regard to the questions--What is right? What is just?

Now to apply the above to one example.

Undoubtedly up to the present time the system of granting Letters of
Marque to the adventurers of a power friendly to the enemy, has
received the sanction of the world. These buccaneering adventurers
have, under the laws of war, when taken, claimed and been allowed the
rights of prisoners of war; have exercised all the privileges of
regular privateers, and cast little or no responsibility on the
countries they issued from, who still claimed to be entitled to the
full position of neutral powers. Yet these unprincipled men differed
from pirates in one respect only--that their infamous warfare was
waged on one unhappy nation alone, instead of against the power of
mankind. Uninfluenced by national feelings, their sole object was the
plunder of the honest trader, and the means to that end--murder. Are
there any modern principles of right and justice by which such persons
are still to claim consideration? That there were such principles
formerly, when the whole system of war was barbaric and unmerciful,
cannot be doubted, unless such enemies were to be condemned when
others equally bad were to be excused; but those reasons have now
disappeared. Universal opinion is against these principles; numerous
treaties have condemned the practice; the municipal laws of several
states have made it punishable in their own subjects; America has even
attempted, in two cases, to bring it in as piracy; and the highest
authorities have pronounced it a crime.

Are not then the foundations of the laws that governed this case
changed? It may be going too far to declare it piracy by the Law of
Nations, but is it asking too much, in calling upon our maritime