Summarizing How is power divided between the federal and state governments?

The Federal System
,
The framers of the Constitution wanted to create a government
powerful enough to protect the rights of citizens and defend the
country against its enemies. To do so, they set up a federal system
of government, a system that divided powers between the states
and the federal government.
The Constitution assigns certain powers to the national government.
These are called delegated powers. Among them are the rights
to coin money and to regulate trade. Reserved powers are those kept
by the states. These powers include creating local governments and
holding elections. Concurrent powers are those shared by the federal
a~d state governments. They include taxing, borrowing money, and
enforcing laws.
Sometimes, Congress has had to stretch its delegated powers to
deal with new or unexpected issues. A clause in the Constitution
states that Congress may "make all Laws which shall be necessary
and proper" for carrying out its duties. This clause, called the elastic
clause-because it can be stretched (like elastic)-provides flexibility
for the government.