穀物法
Like Adam Smith, Ricardo was an opponent of protectionism for national economies, especially for agriculture. He believed that the British "Corn Laws" – imposing tariffs on agricultural products – ensured that less-productive domestic land would be cultivated and rents would be driven up . Thus, profits would be directed toward landlords and away from the emerging industrial capitalists. Ricardo believed landlords tended to squander their wealth on luxuries, rather than invest. He believed the Corn Laws were leading to the stagnation of the British economy. In 1846, his nephew John Lewis Ricardo, MP for Stoke-upon-Trent, advocated free trade and the repeal of the Corn Laws.