Page "Article One of the United States Constitution" Paragraph 10

Although not specifically mentioned in the Constitution, Congress has also long asserted the power to investigate and the power to compel cooperation with an investigation.

The Supreme Court has affirmed these powers as an implication of Congress's power to legislate.

Since the power to investigate is an aspect of Congress's power to legislate, it is as broad as Congress's powers to legislate.

However, it is also limited to inquiries that are " in aid of the legislative function ;" Congress may not " expose for the sake of exposure.

" It is uncontroversial that a proper subject of Congress's investigation power is the operations of the federal government, but Congress's ability to compel the submission of documents or testimony from the President or his subordinates is often-discussed and sometimes controversial ( see executive privilege ), although not often litigated.

As a practical matter, the limitation of Congress's ability to investigate only for a proper purpose (" in aid of " its legislative powers ) functions as a limit on Congress's ability to investigate the private affairs of individual citizens ; matters that simply demand action by another branch of government, without implicating an issue of public policy necessitating legislation by Congress, must be left to those branches due to the doctrine of separation of powers.

The courts are highly deferential to Congress's exercise of its investigation powers, however.

Congress has the power to investigate that which it could regulate, and the courts have interpreted Congress's regulatory powers broadly since the Great Depression.