Putting Nature and Nations Asunder 157Suárez explained, the ius gentium “has such a close relationship to nature...
that it has grown, almost by a natural pro cess, with the growth of the
human race.” Natural law therefore provides a certain mea sure of guid-
ance to the content of the ius gentium— but this is merely in the nature of a
general indication, since Suárez adhered consistently to the position that the
ius gentium is not derivable from natural law by the canons of logical deduc-
tion alone.
In certain respects at least, the two bodies of law were envisaged as work-
ing in a kind of partnership, with the ius gentium operating, so to speak,
closer to the ground. While natural law prescribes and forbids certain forms
of conduct, it does not specify penalties for infringement. In legal parlance,
it would be said that natural law operates exclusively at the normative level—
meaning that its task is to articulate standards of conduct. Th e important
ancillary task of enforcement falls within the purview of the ius gentium.
Th e illustrations that Suárez gave were the enslavement of prisoners of war
and the capture of enemy property by the just side in war. He explained
these as punitive mea sures, infl icted upon the unjust side for its wrongful
and violent re sis tance to the rule of law. As such, they are features of the ius
gentium rather than of natural law.
According to Suárez, the ius gentium can depart from the natural law in
refraining from imposing punishments for violations of certain natural- law
rules— although the ius gentium cannot, of course, actually contradict or
annul the laws of nature themselves. As examples, he gave prostitution and
the use of deception in contracts (provided that it was “not excessive”). Al-
though natural law forbids both of these acts, it is common for states to re-
frain from infl icting punishments for them. Such acts are still evil, to be
sure, and, as such, they continue to be prohibited by natural law. But they
are not punishable in human courts of justice. Th e ius gentium may there-
fore be regarded as, in general, more tolerant of human foibles and moral
weaknesses than the more rigorous and unbending law of nature.
For a concrete illustration of the interrelation between the two bodies of
law, Suárez appealed to diplomatic law. Th e admission of ambassadors from
foreign states into a state’s territory, he maintained, is not obligatory under
natural law, but it is required by the ius gentium. Once a ruler elects to admit
a foreign ambassador, however, natural law kicks in to provide the ambassa-
dor with a range of immunities from the local law. In Suárez’s explanation,