I read this from this article yesterday. I highly recommend it. I found this statement on the conclusion of many classical liberal thinkers regarding peace and capitalism quite intriguing:
Under a system of private ownership of the means of production and free enterprise, with the only function of government being to protect individuals against violent or fraudulent attacks on their lives, health, or property, it is immaterial for the citizens of any nation where the frontiers of their country are drawn. It is of no concern for anyone whether his country is big or small, and whether it conquers a province or not. The individual citizens do not derive any profit from the conquest of a territory.
It is different with the princes or ruling aristocracies. They can increase their power and their tax revenues by expanding the size of their realms. They can profit from conquest. They are bellicose, while the citizenry is peace loving.
Hence, the old liberals concluded, there would be no more wars under a system of economic laissez faire and popular government. Wars would become obsolete because the causes for war would disappear. Since these 18th- and 19th-century classical liberals were fully convinced that nothing could stop the movement toward economic freedom and political democracy, they were certain that mankind was on the eve of an age of undisturbed peace.
What was needed to make the world safe for peace, they argued, was to implement economic freedom, free trade and goodwill among the nations, and popular government. I want to stress the importance of both of these requirements: free trade at home and in international relations, and democracy. The fateful error of our age has consisted in the fact that it dropped the first of these requirements, namely free trade, and emphasized only the second one, political democracy. In doing so, people ignored the fact that democracy cannot be permanently maintained when free enterprise, free trade, and economic freedom do not exist.