Adam Smith on defence

Always worth reminding ourselves of what a prudent Scot had to say....

The art of war, however, as it is certainly the noblest of all arts, so in the progress of improvement it necessarily becomes one of the most complicated among them. The state of the mechanical, as well as of some other arts, with which it is necessarily connected, determines the degree of perfection to which it is capable of being carried at any particular time.

Adam Smith, The Wealth of Nations, V.i.1

THE first duty of the sovereign, that of protecting the society from the violence and invasion of other independent societies, can be performed only by means of a military force. But the expense both of preparing this military force in time of peace, and of employing it in time of war, is very different in the different states of society, in the different periods of improvement.

-WN V.i.a.1: 699

By diminishing the number of sellers, therefore, we necessarily diminish that of buyers, and are thus likely not only to buy foreign goods dearer, but to sell our own cheaper, than if there was a more perfect freedom of trade. As defence, however it is of much more importance than opulence, the Act of Navigation is, perhaps, the wisest of all the commercial regulations of England.

WN IV.ii.30: 464-5

If any particular manufacture was necessary, indeed, for the defence of the society, it might not always be prudent to depend upon our neighbours for the supply; and if such manufacture could not otherwise be supported at home, it might not be unreasonable that all the other branches of industry should be taxed in order to support it. The bounties upon the exportation of British-made sailcloth and British-made gunpowder may, perhaps, both be vindicated upon this principle.

-The Wealth of Nations/Book IV/Chapter 5