Third in line for the presidency is the President pro tempore of the United States Senate. As of January 2025, that is Senator Chuck Grassley of Iowa, a 92-year-old Republican who was sworn in on January 3, 2025.1Senator Chuck Grassley. President Pro Tempore He would be called on only if both the President and Vice President could not serve and the Speaker of the House was also unavailable.
Who the President Pro Tempore Is
The President pro tempore is a senator chosen by the full Senate to preside over floor sessions when the Vice President is absent. By long-standing tradition, the majority party gives the title to its most senior member. Grassley, who has served in the Senate since 1981, succeeded Senator Patty Murray in the role.1Senator Chuck Grassley. President Pro Tempore
The job carries duties beyond presiding. The President pro tempore jointly appoints the director of the Congressional Budget Office with the Speaker, makes appointments to national commissions and advisory boards, and can administer oaths and sign legislation when the Vice President is not available.2United States Senate. About the President Pro Tempore Unlike the Vice President, they cannot break tie votes on the Senate floor. They remain a regular voting senator in every other respect.
What “Third in Line” Actually Means
Being third in line does not mean automatically becoming President. If the President pro tempore is ever called on, they serve as “acting President,” not President. Under the 25th Amendment, only the Vice President truly becomes President when the office is permanently vacant.3Congress.gov. U.S. Constitution – Twenty-Fifth Amendment Every other successor holds the powers and duties of the office without holding the office itself, and only through the end of the current presidential term or until someone higher on the list becomes available.
Stepping in also carries a permanent cost. The succession statute requires any legislative leader who takes over to first resign both their leadership post and their seat in Congress.4Office of the Law Revision Counsel. 3 U.S. Code 19 – Vacancy in Offices of Both President and Vice President; Officers Eligible to Act There is no serving temporarily and then returning to the Senate afterward.
The statute also includes a “bumping” rule. If a Cabinet secretary is already serving as acting President because no legislative leaders were available, and the House later elects a new Speaker, that Speaker can displace the Cabinet secretary.4Office of the Law Revision Counsel. 3 U.S. Code 19 – Vacancy in Offices of Both President and Vice President; Officers Eligible to Act The provision has never been tested.
Eligibility to Serve
The succession statute applies only to officials who are eligible to serve as President under the Constitution.4Office of the Law Revision Counsel. 3 U.S. Code 19 – Vacancy in Offices of Both President and Vice President; Officers Eligible to Act The President pro tempore must be a natural-born citizen, at least 35 years old, and a resident of the United States for at least 14 years.5Constitution Annotated. Article II Section 1 Clause 5 If the person holding the office does not meet those qualifications, the law skips them and moves to the next eligible successor. The Senate’s tradition of picking its most senior majority-party member makes this scenario unlikely for the President pro tempore specifically, but the safeguard runs down the full succession list.
Where the Rule Comes From
The order of succession is set by 3 U.S.C. § 19, a federal law passed in 1947. That statute placed the Speaker of the House first among legislative leaders, followed by the President pro tempore, then the Cabinet secretaries in the order their departments were created.6Congress.gov. Amdt20.S4.1 Congress’s Power to Provide Further for Presidential Succession Before 1947, Congress had removed legislative leaders from the line entirely in 1886, leaving only Cabinet secretaries in the succession order.7United States Senate. Presidential Succession Act
Legal scholars have argued for decades over whether the 1947 arrangement is even constitutional. The Constitution says Congress can declare “what Officer” shall act as President, and the fight is over what “Officer” means. One camp argues the term covers only executive branch officials, because the Constitution elsewhere makes clear that members of Congress are not “Officers of the United States”; the Incompatibility Clause in Article I, Section 6 bars anyone holding “any Office under the United States” from simultaneously sitting in Congress. The other side notes that the Succession Clause uses the unmodified word “Officer” without limiting it to a branch, and that Article I identifies both the Speaker and President pro tempore as officers of their chambers.8Congress.gov. Presidential Succession: Perspectives and Contemporary Issues No court has ever ruled on the question, so the 1947 act stands.
The Full Order of Succession
After the President pro tempore, the line moves into the Cabinet. Departments are ranked by the date each was established:9USAGov. Order of Presidential Succession
- 1st: Vice President
- 2nd: Speaker of the House
- 3rd: President pro tempore of the Senate
- 4th: Secretary of State
- 5th: Secretary of the Treasury
- 6th: Secretary of Defense
- 7th: Attorney General
- 8th: Secretary of the Interior
- 9th: Secretary of Agriculture
- 10th: Secretary of Commerce
- 11th: Secretary of Labor
- 12th: Secretary of Health and Human Services
- 13th: Secretary of Housing and Urban Development
- 14th: Secretary of Transportation
- 15th: Secretary of Energy
- 16th: Secretary of Education
- 17th: Secretary of Veterans Affairs
- 18th: Secretary of Homeland Security
Every person on the list must meet the same constitutional qualifications, and anyone who does not is passed over.4Office of the Law Revision Counsel. 3 U.S. Code 19 – Vacancy in Offices of Both President and Vice President; Officers Eligible to Act