The U.S. most certainly is a <i>proponent</i> of free trade, even if we aren't the best <i>practitioner</i> of free trade.<p>As far as I know, only one country ever practiced fully free trade, and that was Great Britain for about thirty years starting in 1846 (after the repeal of the Corn Laws, a feat accomplished in part by David Ricardo, who you might remember came up with the theory of comparative advantage).  This time period was more or less the height of the British Empire's power.