How provision of services like defence, often represented as closest to purely public
among major spending items, is affected by population size and composition depends
on politically contentious questions about its purpose. To the extent that defence
spending is about protection of borders and projection of military power in defence of
interests overseas it may be regarded as close to purely public and, therefore,
unaffected by population growth; to the extent that the armed services might be
regarded as ultimate guarantor of the established domestic order, size and composition
of the population may be regarded as more important.