State leaders, led by states' rights advocates such as William Smith and Thomas Cooper, blamed most of the state's economic problems on the Tariff of 1816 and national internal improvement projects. Soil erosion and competition from the New Southwest were also very significant reasons for the state's declining fortunes. George McDuffie was a particularly effective speaker for the anti-tariff forces, and he popularized the Forty Bale theory. McDuffie argued that the 40% tariff on cotton finished goods meant that "the manufacturer actually invades your barns, and plunders you of 40 out of every 100 bales that you produce." Mathematically incorrect, this argument still struck a nerve with his constituency. Nationalists such as Calhoun were forced by the increasing power of such leaders to retreat from their previous positions and adopt, in the words of Ellis, "an even more extreme version of the states' rights doctrine" in order to maintain political significance within South Carolina.