The wealth of a neighbouring nation…though dangerous in war and politics, is certainly advantageous in trade. In a state of hostility it may enable our enemies to maintain fleets and armies superior to our own but in a state of peace and commerce it must likewise enable them to exchange with us to a greater value, and to afford a better market, either for the immediate produce of our own industry, or for whatever is purchased with that produce. As a rich man is likely to be a better customer to the industrious people in his neighbourhood, than a poor, so is likewise a rich nation. A rich man, indeed, who is himself a manufacturer, is a very dangerous neighbour to all those who deal in the same way. All the rest of the neighbourhood, however, by far the greatest number profit by the good market which his expense affords them. They even profit by his underselling the poorer workmen who deal in the same way with him. The manufacturers of a rich nation, in the same manner, may no doubt be very dangerous rivals to those of their neighbours. This very competition, however, is advantageous to the great body of the people, who profit greatly besides by the good market which the great expense of such a nation affords them in every other way. Private people who want to make a fortune, never think of retiring to the remote and poor provinces of the country, but resort either to the capital, or to some of the great commercial towns. They know, that, where little wealth circulates, there is little to be got, but that where a great deal is in motion, some share of it may fall on them. The same maxims which would in this manner direct the common sense of one, or ten, or twenty individuals, should regulate the judgment of one, or ten, or twenty millions, and should make a whole nation regard the riches of its neighbours, as a probable cause and occasion for itself to acquire riches. A nation that would enrich itself by foreign trade, is certainly most likely to do so when its neighbours are all rich, industrious, and commercial nations. A great nation surrounded on all sides by wandering savages and poor barbarians might, no doubt, acquire riches by the cultivation of its own land,s and by its own interior commerce, but not by foreign trade. It seems to have been in this manner that the ancient Egyptians and the modern Chinese acquired their great wealth. The ancient Egyptians, it is said, neglected foreign commerce, and the modern Chinese, it is known, hold it in the most utmost contempt, and scare deign to afford it the decent protection of the laws. The modern maxims of foreign commerce, by aiming at the impoverishment of all our neighbors, so far as they are capable of producing their intended effect, tend to render the very commerce insignificant and contemptible.
It is in consequence of these maxims that the commerce between France and England has in both countries been subjected to so many discouragements and restraints. If those two countries, however. were to consider their real interest, without either mercantile jealousy or national animosity, the commerce of France might be more advantageous to Great Britain than tha of any other country, and for the same reason that of Great Britain to France. France is the nearest neighbour to Great Britain. In the trade between the southern coast of England and the northern and north-western coasts of France, the returns might be expected , in the same mannener as in inland trade, four, five, or six times in the year. The capital, therefore, employed in this trade, cold in each of the two countries keep in motion four, five, or six times the quantity of the industry, and afford employment and subsistence to four , five, or six times the number of people, which an equal capital could do in the greater part of the other brances of foreign trade.
...But the very same circumstances which would have rendered an open and free commerce between the two countries so advantageous to both, have occasioned the principal obstructions to that commerce. Being neighbours, they are necessarily enemies, and the wealth and power of each becomes, upon that account, more formidable to the other; and what wold increase the advantage of national friendship, serves only to inflame the violence of national animosity. They are both rich and industrious nations; and the merchants and manufacturers of each, dread the competition of the skill and activity of those of the other. Mercantile jealousy is excited, and both inflames, and is itself inflalmed, by the violence of national animosity: and the traders of both countries have announced, with all the passionate confidence of interested falsehood, the certain ruin of each, in consequence of that unfavourable balance of trade, which they pretend, would be the infallible effect of an unrestrained commerce with the other.
There is no commercial country in Europe of which the approaching ruin has not frequently been foretold by the pretended doctors of this system, from an unfavourable balance of trade. After all the anxiety, hwoever, which they have excited about this, after all the vain attempts of almost all trading nations to turn that balance in their own favour and against their neighbours, it does not appear that any one nation in Europe has been in any respect impoverished by this cause. Every town and country, on the contrary, in proportion as they have opened their ports to all nations, instead of being ruined by this free trade, s the principles of the commercial system would lead us to expect, ahve been enriched by it. Thought there are in Europe, indeed, a few towns which in some respects deserve the name of free ports, there is no country which does so. Holland, perhaps, approaches the nearest to this character of any, though still very remote from it; and Holland, it is acknowledged, not only derives its whole wealth, but a great part of its necessary subsistence, from foreign trade.
(Adam Smith, the Wealth of Nations, pp. 461-464 , Modern Library edition).