“You must first enable the government to control the governed; and in the next place oblige it to control itself.” James Madison, Federalist No. 51, 1788
The framers of the U.S. Constitution wanted the federal government to have only limited power. Therefore, they limited the kinds of cases federal courts can decide. Most laws that affect us are passed by state governments, and thus state courts handle most disputes that govern our daily lives.
This is the fundamental idea behind Federalism, which means a government in which power is divided between one national government and other, smaller state or regional governments.