Still in those early days trade depended not upon the quality of the goods but upon the military force to control the markets. The Dutch consequently valued the island chiefly on account of its strategical position. From Formosa the Spanish commerce between Manila and China, and the Portuguese commerce between Macau and Japan could by constant attacks be made so precarious that much of it would be thrown into the hands of the Dutch, while the latter’s dealings with China and Japan would be subject to no interruptions.
James W. Davidson, The Island of Formosa, Past and Present (1903).
Here Davidson nicely contrasts monopolies based on product quality with monopolies based on force, capitalism with mercantilism. I do not think it is too much to say that democracy, or at least a genuine republicanism, even if autocratic in administration, is the principal bulwark between the two, and that antitrust, when used properly, is meant to round off any remaining mercantilist edges.
When used improperly, antitrust is of course a gunboat all of its own.