The oath of office for Congress is a short statutory pledge — set by 5 U.S.C. § 3331 and required by Article VI of the Constitution — in which every senator and representative swears or affirms to support and defend the Constitution before they can vote, introduce legislation, or exercise any power of the office.1Congress.gov. U.S. Constitution – Article VI2Office of the Law Revision Counsel. 5 USC 3331 – Oath of Office Until a member-elect completes the oath, they are not seated.3U.S. Government Publishing Office. House Practice – Chapter 33 Oaths
What the Oath Says
The statutory text every member repeats is this:
I, [name], do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God.2Office of the Law Revision Counsel. 5 USC 3331 – Oath of Office
The choice between “swear” and “affirm” is written into the statute for members whose religious or philosophical beliefs prevent them from swearing. Article VI separately forbids any religious test as a qualification for federal office, so no member can be required to profess a faith to serve.1Congress.gov. U.S. Constitution – Article VI The closing phrase “So help me God” appears in the statute but is not treated as a legal requirement for a valid oath. No religious text is required on the floor either; a Bible or other book appears only in family reenactments held after the official ceremony.
Who Administers the Oath
House
Federal law says that at the start of each new Congress, “any Member” of the House may administer the oath to the Speaker, and the Speaker then administers it to everyone else.4Office of the Law Revision Counsel. 2 USC 25 – Oath of Speaker, Members, and Delegates By tradition, the Dean of the House — the representative with the longest continuous service — swears in the Speaker, though the House has departed from that custom on occasion.5U.S. House of Representatives. Fathers/Deans of the House Once the Speaker is seated, the Speaker swears in the remaining members, delegates, and the Resident Commissioner before any other business.
Senate
The statute assigns this role to the President of the Senate, meaning the Vice President.6Office of the Law Revision Counsel. 2 USC 21 – Oath of Senators When the Vice President is unavailable, the Senate passes a resolution letting another senator handle it, typically the President pro tempore.
How the Ceremony Works
The Twentieth Amendment fixes the opening of each new Congress at noon on January 3, unless Congress passes a law setting a different date.7Congress.gov. U.S. Constitution – Twentieth Amendment Because the whole House and about a third of the Senate are up every two years, opening day always brings a large swearing-in.
House Floor Procedure
The House swears in members as a group. After the Speaker takes the oath, every other member-elect stands, raises the right hand, and answers the oath as the Speaker reads it aloud in question form.8Congress.gov. A Guide to Proceedings on the House Floor The whole thing takes minutes. No individual member walks to the podium during the official ceremony.
Senate Floor Procedure
The Senate does it one at a time. Each newly elected or reelected senator is escorted down the center aisle to the presiding officer’s desk, usually by the senator’s home-state colleague. The presiding officer reads the oath, the senator agrees, and the senator then signs a page in the Senate’s oath book before the next senator is called forward.9United States Senate. When a New Congress Begins With only about a third of the chamber turning over, the individual approach is workable in a way it wouldn’t be for the 435-member House.
The oath book itself dates to a Senate resolution from January 1864, when the wartime chamber required members to formally subscribe to the loyalty oath in writing.10United States Senate. Oath of Office The oath changed; the signing survived.
Family Reenactments
Members of both chambers commonly hold ceremonial reenactments with their families in ornate rooms around the Capitol after the official proceedings. Some senators hold a personal Bible or other meaningful text for these photos. The reenactments carry no legal weight. The only binding oath is the one taken on the floor.
Mid-Term and Special-Election Swearing-In
Not every member takes the oath on opening day. When a House seat opens mid-session due to death, resignation, or expulsion, the winner of the special election presents a certificate of election to the Clerk, and the Speaker administers the oath without needing unanimous consent or a quorum present.11U.S. Government Publishing Office. Precedents of the House – Oaths If the certificate hasn’t arrived yet but the result isn’t disputed, the House will often grant unanimous consent to swear in the presumed winner anyway.
Senate vacancies work differently. Under the Seventeenth Amendment, state governors can appoint a replacement senator to serve until the next election, depending on state law.12United States Senate. Appointed Senators An appointed senator takes the same oath as any elected senator, usually within a short window after the appointment while the Senate arranges the logistics.
When a Swearing-In Is Challenged
Article I, Section 5 lets each chamber judge the qualifications of its own members by majority vote, and the House uses that power at the oath stage. If another member challenges a member-elect’s qualifications or election, the challenged individual can be asked to step aside while the rest of the body is sworn in.3U.S. Government Publishing Office. House Practice – Chapter 33 Oaths
Being challenged doesn’t automatically mean losing the seat. The House can pass a resolution allowing the oath to be administered with conditions, such as referring the final determination to a committee. The member-elect can also voluntarily defer taking the oath until the dispute is resolved, without formally declining the seat. If a member-elect simply fails to appear, the House can eventually declare the seat vacant.
The Oath’s Ongoing Force
The oath isn’t only a ceremonial gate. Section 3 of the Fourteenth Amendment bars anyone who previously swore an oath to support the Constitution as a member of Congress or federal officer and then “engaged in insurrection or rebellion” or “given aid or comfort to the enemies thereof” from ever serving again as a senator, representative, presidential elector, or any federal or state officeholder.13Congress.gov. Fourteenth Amendment Section 3 – Disqualification from Holding Office Congress can lift that disqualification only by a two-thirds vote in both chambers.
A separate statute, 5 U.S.C. § 7311, bars anyone who advocates overthrowing the constitutional form of government, or who participates in a strike against the federal government, from holding a government position.14Office of the Law Revision Counsel. 5 U.S. Code 7311 – Loyalty and Striking Its main reach is federal employees generally, but it reflects the same principle: the oath creates continuing legal obligations, not a one-time formality.