Our analysis starts with the succession clause in Article II of the Constitution. The Constitution specifies that the vice president serves when the presidency goes vacant. But what happens if both positions go vacant, a so-called double vacancy? The Constitution’s succession clause states: “Congress may by Law … [declare] what Officer shall then act as President.” And Congress has done just that: The Presidential Succession Act places the speaker of the House next in line after the vice president. If the speaker is an officer, then there is no problem, because the Constitution clearly states that Congress may place officers in the line of succession.

Read more: Rewriting the rules of presidential succession

That’s where the law professors (and brothers) Akhil Reed Amar and Vikram David Amar take issue. They wrote in a 1995 article that the speaker, a member of the legislative branch, cannot be characterized as an officer.

The Constitution uses different phrases in reference to different types of offices and officers, such as “officers of the United States” and “office under the United States.” The Amars write that each of these phrasings, as well as the phrase officer in the succession clause, “seemingly describes the same stations.”

As evidence, the Amars point to the fact that in an early draft of the Constitution, the succession clause expressly extended to “officers of the United States,” but a style committee changed this language to “officers.” Finding nothing in the Philadelphia Convention’s records that indicates the committee intended to make a substantive change, the Amars assume that officer was “shorthand” for the longer phrase. For this reason and others, they conclude that all these variations on office and officer have the same scope, and that all these phrases refer only to positions in the judicial and executive branches, including the presidency. Officials in the legislative branch, however, are not officers, they say. As a result, members of Congress fall outside the scope of the succession clause; therefore, the Amars would conclude that Pelosi cannot succeed to the presidency. Their position treats the Framers’ carefully chosen textual variations as irrelevant.

We disagree. The Framers used each of these different phrasings to accomplish different purposes. Presumptively, when different language is used, different meanings are intended. The phrase officers of the United States was the only phrase the Framers chose to refer to appointed executive- and judicial-branch officers; it did not extend to appointed officers in the legislative branch, such as the secretary of the Senate and the clerk of the House. When they wanted to refer to elected positions, generally, the Framers named them, such as president, vice president, senators, and representatives. Where the Framers chose other language, such as office under the United States, they drew the line not between the branches, but between appointed officers and elected officials in all three branches of government. In short, office under the United States encompasses appointed officers in all three branches, but not any elected officials.