… believes that we Americans would be even wealthier than we now are if each of the 50 states were a sovereign nation that restricted its citizens’ abilities to import goods and services not only from Europe, Asia, and other far away places, but also from each of the other 49 states. After all, if creating artificial scarcities in the United States is key to increasing each American’s access to goods and services, imagine how much richer we Americans would be if we in Virginia enjoyed the artificial scarcities created by the government in Richmond obstructing our access not only to goods and services sold by the likes of Canadians and the Chinese, but also to goods and services sold by the likes of North Carolinians, Marylanders, Californians, Hawaiians, and Americans in other states. Ditto for Louisianans whose wise leaders in Baton Rouge obstructed their ability to import goods and services not only from places such as Mexico and Japan, but also from places such as Mississippi, Texas, New Jersey, and other U.S. states. Ditto also for Oklahomans, Nebraskans, Minnesotans, Floridians, Vermonters, Arizonans, Alaskans, and citizens of each of the other states.
Or put somewhat differently, a protectionist is someone who regards American courts as having visited upon Americans a curse rather than a blessing through these courts’ consistent interpretation of the U.S. Constitution as meant to create among these united states a free-trade zone.
See also here.