The Interstate commerce clause only gives the federal government the power to regulate the large-scale transportation of goods between the states. Before the constitution was ratified the United States operated under the Articles of Confederation. The federal government created by the Articles lacked the power to prevent the states from interfering with the free flow of goods through their borders.
States with good harbors would placeahigh import duty on goods meant for states lacking good harbors. Some states would charge ridiculous taxes on goods that were merely passing through their borders. Because of the interference commerce between the states nearly ground toahalt and open conflicts nearly broke between some of the states.
The framers of the constitution wrote the interstate commerce clause to grant the US Congress alone the power to regulate the transportation of goods between the states.
The framers never intended to grant the federal government the power to manage or regulate the lives of individuals or any groups of people. Neither this clause nor any other in the Constitution grant the federal government the power to force us to do anything. The “farm bill” goes way beyond regulating the interference of the free flow of goods between the states. It is essentially another welfare program. http://www.washingtonpost.com/blogs/wonkblog/wp/2013/06/10/the-senate-is-voting-on-a-955-billion-farm-bill-heres-whats-in-it/