Concurrent powers of the United States government are actions that can be performed by both state and national government. State and local governments seldom exercise concurrent powers in accordance with each other. They do, however, usually exercise them simultaneously.
The United States is a unique country because it has a government at the national level as well as state governments that operate independently. Although the national policy blankets the entire nation, state policy sometimes varies greatly from state to state. Sometimes states disagree with national policy and impose their own laws. Sometimes the national government allows this to happen. A contemporary example is the legalization of marijuana. Marijuana is illegal on a federal level. Some states, however, disagree and have passed laws legalizing marijuana within their borders. The federal government has said that it will not impose on rights of these to do so. Likewise, the federal government sometimes intervenes when it feels states impose laws that are unfair. This usually happens in regard to issues of civil rights. There are some areas of government, however, in which both state and federal government have equal power to exercise power independently and concurrently. Taxes are a primary example of concurrent powers. The majority of the nation's citizens pay both federal and state taxes.