Oh really?
In his Report on Manufactures Treasury Secretary Alexander Hamilton proposed a far-reaching scheme to use protective tariffs as a lever for rapid industrialization. Some of Hamilton's recommendations resulted in upward tariff revisions in 1790 and 1792
After the War of 1812, tariffs were raised sharply. Hatred of England was one reason; the primary goal was protection for the manufacturing industries that now were growing rapidly in the Northeast
Senator Daniel Webster, formerly a spokesperson for Boston's merchants who imported goods (and wanted low tariffs), switched dramatically to represent the manufacturing interests in the Tariff of 1824. Rates were especially high for bolts of cloth and for bar iron, of which Britain was a low-cost producer
Henry Clay and his Whig Party, envisioning a rapid modernization based on highly productive factories, sought a high tariff. Their key argument was that startup factories, or "infant industries," would at first be less efficient than European (British) producers. Furthermore, American factory workers would be paid higher wages than their European competitors. The arguments proved highly persuasive in industrial districts. Clay's position was adopted in the 1828 and 1832 Tariff Acts.
Legislators such as Justin Morrill and economist Henry Carey began to push for a restoration of the Whig American System program of protective tariffs. The first of these was passed in early 1861 and bears the name of the Morrill Tariff.
And the result of these protectionist tariffs was
American industry and agriculture—and industrial workers—had become the most efficient in the world by the 1880s. They were not at risk from cheap imports. No other country had the industrial capacity, the high efficiency and low costs, or the complex distribution system needed to compete in the vast American market. Indeed, it was the British who watched in stunned horror as cheaper American products flooded their home islands. Wailed the London Daily Mail in 1900.
The election of 1888 was fought primarily over the tariff issue, and Cleveland lost. Republican Congressman William McKinley argued, "Free foreign trade gives our money, our manufactures, and our markets to other nations to the injury of our labor, our tradespeople, and our farmers. Protection keeps money, markets, and manufactures at home for the benefit of our own people."
McKinley campaigned heavily in 1896 on the tariff as a positive solution to depression. Promising protection and prosperity to every economic sector, he won a smashing victory. The Republicans rushed through the Dingley tariff in 1897
Woodrow Wilson made a drastic lowering of tariff rates a major priority for his presidency. The 1913 Underwood Tariff cut rates, but the coming of world war in 1914 radically revised trade patterns. Reduced trade and, especially, the new reveues generated by the federal income tax made tariffs much less important. When the Republicans regained power after the war they restored the usual high rates.
The GOP under Ronald Reagan and George H.W. Bush abandoned the protectionist ideology, and came out against quotas and in favor of the GATT/WTO policy of minimal economic barriers to global trade.
Free trade with Canada came about as a result of the Canada-U.S. Free Trade Agreement of 1987, which led in 1994 to the North American Free Trade Agreement, NAFTA. It was based on George H. W. Bush's plan to enlarge the scope of the market for American firms to include Canada and Mexico. US President Bill Clinton, with strong Republican support, pushed NAFTA through Congress over the vehement objection of labor unions. Likewise in 2000 he worked with Republicans to give China entry into WTO and "most favored nation" trading status (i.e., low tariffs). NAFTA and WTO advocates promoted an optimistic vision of the future, with prosperity to be based on intellectuals skills and managerial know-how more than on routine hand labor.
As I have clearly documented protectionism is CONSERVATIVE. Protectionism was GOP policy, and American policy thru out most of or history.
Have fun refuting that!