What is the Difference Between State and Federal Law?

State governments have the power to determine what constitutes a crime statutorily (through the legislature) and through common law. They also have the power to protect their citizens from criminal activity by prosecuting criminals. In contrast, the federal government has limited jurisdiction and must link any crimes it prosecutes to its Constitutional powers such as the commerce power, the taxing power, and the postal power. Examples of successful federal criminal legislation are the federal gun laws, federal drug laws, and federal computer laws.