Investigate the executive
Congress can compel testimony and documents from the executive branch (and private parties) in aid of its legislative work. Hearings, subpoenas, and contempt citations are how the funding-and-lawmaking branch finds out what is actually happening.
No clause grants an investigative power. The Supreme Court holds it is implied: Congress cannot legislate or appropriate wisely about what it cannot examine (McGrain v. Daugherty, 1927).
Congress, through its committees
How it works in practice
Committees hold hearings and issue subpoenas under each chamberOne of the two houses of a legislature. Congress has two: the House of Representatives and the Senate. A bill must pass both, in identical text.Read the full definition (opens a new tab)'s rules. Non-compliance can be met with contempt of CongressThe sanction for defying a congressional subpoena. Three routes exist: criminal referral to the Justice Department, a civil suit, and the long-dormant inherent contempt power.Read the full definition (opens a new tab) (criminal referralThe assignment of a newly introduced measure to the committee (or committees) with jurisdiction over its subject.Read the full definition (opens a new tab), civil enforcement, or the chambers' dormant inherent power). The recurring counterweight is executive privilegeA President's claimed right to withhold certain communications from Congress or the courts, so advisers can speak candidly. It is not absolute and is not in the Constitution.Read the full definition (opens a new tab), which shields some presidential communications and is resolved, when pressed, by judiciaryThe branch of government made up of the courts and judges. The federal judiciary is the Supreme Court plus the courts Congress created beneath it.Read the full definition (opens a new tab) (United States v. Nixon; Trump v. Mazars).