Clay's American System program had three components: a national bank, to provide the nation with a sound currency and stable financial system; high tarriffs, to encourage the growth of domestic manufacturing; and federal spending, financed by tariffs, to create roads, bridges, canals, and other transportation infrastructure to aid in the development of the domestic economy [and for military purposes, too]. Garfinkle, p 34 - 35
Clay supported domestic manufacturing, to insulate the United States from dependence on the United Kingdom.
Clay also saw his American System as something that would aid the common people -- by promoting economic development. He always claimed to have a concern for ordinary citizens. And he certainly believed in America as a land of opportunity and saw his American System as a way to expand opportunities. Clay was responsible for putting the term "self-made man" into political circulation. But in truth, his concern with the welfare of workers was generally secondary to his nationalistic ambitions for the United States, his vision of America as an emerging world power. Garfinkle, p 35