And no alien government resting on the support of a home population trained in the habits of democracy or given over to ideals of common honesty in national concerns could hopefully undertake the enterprise.

This work of empire-building out of unwarlike materials could apparently be carried out only by some alien power hampered by no reserve of scruple, and backed by a servile populace of its own, imbued with an impeccable loyalty to its masters and with a suitably bellicose temper, as, e.g., Imperial Japan or Imperial Germany.
However, for the commonplace national enterprise the common run will do very well.

Any populace imbued with a reasonable measure of patriotism will serve as ways and means to warlike enterprise under competent management, even if it is not habitually prone to a bellicose temper.
Rightly managed, ordinary patriotic sentiment may readily be mobilised for warlike adventure by any reasonably adroit and single-minded body of statesmen,--of which there is abundant illustration.

All the peoples of Christendom are possessed of a sufficiently alert sense of nationality, and by tradition and current usage all the national governments of Christendom are warlike establishments, at least in the defensive sense; and the distinction between the defensive and the offensive in international intrigue is a technical matter that offers no great difficulty.

None of these nations is of such an incorrigibly peaceable temper that they can be counted on to keep the peace consistently in the ordinary course of events.
Peace established by the State, or resting in the discretion of the State, is necessarily of the nature of an armistice, in effect terminable at will and on short notice.