ll organized to
feel safe against alien aggression, it inevitably became the aggressor
itself; and it inevitably carried the conquest of its neighbors just as
far as it was able. But domestic security, which is reached by constant
foreign aggression, results inevitably in a huge unwieldy form of
imperial political organization which is obliged by the logic of its
situation to seek universal dominion. The Romans made the great attempt
to establish a dominion of this kind; and while their Empire could not
endure, because their military organization destroyed in the end the
very foundation of internal order, they bequeathed to civilization a
political ideal and a legal code of inestimable subsequent value.

As long as men were obliged to choose between a communal or an imperial
type of political organization,--which was equivalent merely to a choice
between anarchy and despotism,--the problem of combining internal order
with external security seemed insoluble. They needed a form of
association strong enough to defend their frontiers, but not
sufficiently strong to attack their neighbors with any chance of
continued success; and such a state could not exist unless its unity
and integrity had some moral basis, and unless the aggressions of
exceptionally efficient states were checked by some effective
inter-state organization. The coexistence of such states demanded in its
turn the general acceptance of certain common moral ties and standards
among a group of neighboring peoples; and such a tie was furnished by
the religious bond with which Catholic Christianity united the peoples
of Western Europe--a bond whereby the disorder and anarchy of the early
Middle Ages was converted into a vehicle of political and social
education. The members of the Christian body had much to fear from their
fellow-Christians, but they also had much to gain. They shared many
interesting and vital subjects of consultation; and even when they
fought, as they usually did, they were likely to fight to some purpose.
But beyond their quarrels Catholic Christians comprised one universe of
discourse. They were somehow responsible one to another; and their
mutual ties and responsibilities were most clearly demonstrated whenever
a peculiarly unscrupulous and insistent attempt was made to violate
them. As new and comparatively strong states began to emerge from the
confusion of the early Middle Ages, it was soon found that under the new
conditions states whi