Ken B. answered 09/26/23
15 years experience teaching AP US Government and Politics
That can be a very involved answer. A quick description would be that due to federalism, there are some governmental actions that can only involve the central government (raising a military, interstate commerce, etc.) and the state government is unable to have any control. There are also some actions in which the state government has total control over and the federal government has no influence over (although throughout most US history, the federal government has inched its way into some of these rights). The shared responsibilities is where things get the most sticky. Shared responsibilities (taxation, roads, etc.) can sometimes lead to conflict between the 2 different types of government and can sometimes lead to Supreme Court cases to decide the constitutional authority.