Explain the impact of the American System on the structure of the American economic system.

I think what you are asking is the impact of the American political system on the American economy.

America adopted the democratic republican system in which the individual freedom and rights were given the utmost importance.

Because of this emphasis on the individual rights, individual property rights and freedoms, a capitalistic economy that values free Commerce was adapted by the USA. Moreover, in this economy, the market prices are set by the demand and supply and the price in turn acts as a signal and and coordinating force for the market.