The structure of the American court system has been viewed as complex and confusing as federal and state courts differ in jurisdiction, and types of cases that can be handled at the many different levels. The Supreme Court is the ultimate decision maker in cases that has been appealed regarding decisions made at the lower level of federal and state Supreme Courts.
The dual court system operates within the boundaries of the state and federal court systems. It is not uncommon for different states to have different laws, while at the federal level it applies to all the states regardless of the instate laws.