So that exemption from these things by a comprehensive neutralisation of trade relations would immediately benefit all the nations concerned, in respect of their material well-being in times of peace.

There is no exception and no abatement to be taken account of under this general statement, as is well known to all men who are conversant with these matters.
But it is otherwise as regards the dynastic interest in the case, and as regards any national interest in warlike enterprise.

It is doubtless true that all restraint of trade between nations, and between classes or localities within the national frontiers, unavoidably acts to weaken and impoverish the people on whose economic activities this restraint is laid; and to the extent to which this effect is had it will also be true that the country which so is hindered in its work will have a less aggregate of resources to place at the disposal of its enterprising statesmen for imperialist ends.

But these restraints may yet be useful for dynastic, that is to say warlike, ends by making the country more nearly a "self-contained economic whole." A country becomes a "self-contained economic whole" by mutilation, in cutting itself off from the industrial system in which industrially it belongs, but in which it is unwilling nationally to hold its place.

National frontiers are industrial barriers.