Enumerated powers

The enumerated powers of the United States Congress are the powers granted to the federal government of the United States by the United States Constitution. Most of these powers are listed in Article One of [the United States Constitution#Section 8: Powers of Congress|Article I, Section 8].
In summary, Congress may exercise the powers that the Constitution grants it, subject to the individual rights listed in the Bill of Rights. Moreover, the Constitution expresses various other limitations on Congress, such as the one expressed by the Tenth Amendment: "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people."
Historically, Congress and the Supreme Court have broadly interpreted the enumerated powers, especially by deriving many implied powers from them. The enumerated powers listed in Article One include both exclusive federal powers, as well as concurrent powers that are shared with the states, and all of those powers are to be contrasted with reserved powers that only the states possess.

List of enumerated powers of the federal constitution

Article I, Section 8 of the United States Constitution:
Article III, Section 3 of the United States Constitution:
Article IV, Section 3 of the United States Constitution:
Amendment XVI of the United States Constitution:
Amendment XX, Section 3 of the United States Constitution:
Amendment XX, Section 4 of the United States Constitution:
Additionally, several amendments include a Congressional power of enforcement in which the language "The Congress shall have the power to enforce this article by appropriate legislation" is used with slight variations, granting to Congress the power to enforce the following amendments:

Political interpretation

There are differences of opinion on whether current interpretation of enumerated powers as exercised by Congress is constitutionally sound.
One school of thought is called strict constructionism. Strict constructionists refer to a statement on the enumerated powers by Chief Justice Marshall in the case McCulloch v. Maryland:

This government is acknowledged by all, to be one of enumerated powers. The principle, that it can exercise only the powers granted to it, would seem too apparent, to have required to be enforced by all those arguments, which its enlightened friends, while it was depending before the people, found it necessary to urge; that principle is now universally admitted.

Another school of thought is referred to as loose construction. They often refer to different comments by Justice Marshall from the same case:

We admit, as all must admit, that the powers of the Government are limited, and that its limits are not to be transcended. But we think the sound construction of the Constitution must allow to the national legislature that discretion with respect to the means by which the powers it confers are to be carried into execution which will enable that body to perform the high duties assigned to it in the manner most beneficial to the people. Let the end be legitimate, let it be within the scope of the Constitution, and all means which are appropriate, which are plainly adapted to that end, which are not prohibited, but consistent with the letter and spirit of the Constitution, are constitutional.

Necessary and Proper Clause

Interpretation of the Necessary and Proper Clause has been controversial, especially during the early years of the country. Strict constructionists interpret the clause to mean that Congress may make a law only if the inability to do so would cripple its ability to apply one of its enumerated powers. Loose constructionists, on the other hand, believe it is largely up to Congress and not the courts to determine what means are "necessary and proper" in executing one of its enumerated powers. It is often known as the "elastic clause" because of the great amount of leeway in interpretation it allows; depending on the interpretation, it can be "stretched" to expand the powers of Congress, or allowed to "contract", limiting Congress. In practical usage, the clause has been paired with the Commerce Clause in particular to provide the constitutional basis for a wide variety of federal laws.

''McCulloch v. Maryland''

The defining example of the Necessary and Proper Clause in U.S. history was McCulloch v. Maryland in 1819. The United States Constitution says nothing about establishing a national bank. The U.S. government established a national bank that provided part of the government's initial capital. In 1819 the federal government opened a national bank in Baltimore, Maryland. In an effort to tax the bank out of business, the government of Maryland imposed a tax on the federal bank. James William McCulloch, a cashier at the bank, refused to pay the tax. Eventually the case was heard before the U.S. Supreme Court. Chief Justice John Marshall held that the power of establishing a national bank could be implied from the U.S. Constitution. Marshall ruled that no state could use its taxing power to tax an arm of the national government.

Case law

The case of United States v. Lopez in 1995 held unconstitutional the Gun Free School Zone Act because it exceeded the power of Congress to "regulate commerce...among the several states". Chief Justice William Rehnquist wrote, "We start with first principles. The Constitution creates a Federal Government of enumerated powers." For the first time in sixty years the Court found that in creating a federal statute, Congress had exceeded the power granted to it by the Commerce Clause.
In National Federation of Independent Business v. Sebelius, the Supreme Court held that the Commerce Clause did not give Congress the authority to require individuals to purchase health insurance. However, since the court ruled that Congress's taxing authority was sufficient to enact the mandate, some constitutional lawyers have argued that the commerce clause discussion should be treated as judicial dictum. Chief Justice John Roberts, in his majority opinion, stated that:
No other justice joined this segment of the Chief Justice's opinion.

Enumerated Powers Act

The Enumerated Powers Act is a proposed law that would require all bills introduced in the U.S. Congress to include a statement setting forth the specific constitutional authority under which each bill is being enacted. From the 104th Congress to the 111th Congress, U.S. Congressman John Shadegg introduced the Enumerated Powers Act, although it has not been passed into law. At the beginning of the 105th Congress, the House of Representatives incorporated the substantive requirement of the Enumerated Powers Act into the House rules.

Tea Party support

The Enumerated Powers Act is supported by leaders of the U.S. Tea Party movement. National Tea Party leader Michael Johns has said that progressives often "see the Constitution as an impediment to their statist agenda. In almost all cases, though, there is very little thought or dialogue given to what should be the first and foremost question asked with every legislative or administrative governmental action: Is this initiative empowered to our federal government by the document's seven articles and 27 amendments? In many cases, the answer is no." "For this reason," Johns said, "we also strongly support the Enumerated Powers Act, which will require Congress to justify the Constitutional authority upon which all legislation is based."