On Thursday, the Supreme Court will hear oral argument in the Colorado case in which voters are challenging former President Donald Trump’s eligibility to appear on that state’s ballot as a candidate for president. The Colorado Supreme Court agreed with those Colorado voters, concluding that Trump’s actions in connection with Jan. 6, 2021, disqualify him from being president under Section 3 of the 14^th Amendment. If the U.S. Supreme Court’s justices adhere to the text and history of the Constitution, they’ll agree.

Added to the Constitution in the wake of the Civil War, Section 3 of the 14^th Amendment bars from public office anyone who took an oath to support the Constitution and subsequently engaged in an insurrection. It was most immediately aimed at purging from office the class of Southern political elites, sometimes called the “Slave Power,” who were believed to bear primary responsibility for the Confederate rebellion, but the amendment’s Framers used broad language to sweep beyond the Civil War context and, as one senator put it in 1866, address “any rebellion hereafter to come.”

Section 3 provides that anyone who engaged in an insurrection after “having previously taken an oath … as an officer of the United States” is disqualified from holding any state or federal office again. In a brief filed last month, Trump argues that the phrase “officer of the United States” does not include the president, which means he can’t be disqualified. In support of this argument, he looks at the original Constitution, written and ratified in the 1780s. No matter what “officer of the United States” meant in the 1860s, he says, the Framers of the 14^th Amendment must have been looking back to the original Constitution, referring to the meaning of the words used at that time.

But that’s not how constitutional interpretation works. The theory that judges should resolve constitutional disputes by looking at what the Constitution’s words meant at the time they were written doesn’t mean that the oldest evidence is the best. Instead, as Justice Clarence Thomas wrote for the court two years ago, judges must give words in the Constitution the meaning “they were understood to have when the people adopted them.” So in this case, the court should look to the 1860s, when the 14^th Amendment was written and ratified, to understand the meaning of the term “officer of the United States” in Section 3.

And there is abundant evidence that Americans in the 1860s understood the president to be an “officer of the United States.” Historians and constitutional lawyers (including in my organization, the Constitutional Accountability Center, which submitted a friend-of-the-court brief in this case) have combed through public documents to understand what the phrase meant at the time. We found many examples in which members of Congress—including members of the 39^th Congress, who wrote the 14^th Amendment and sent it to the states for ratification—used the word “officer” to refer to the president. We found that lawyers and judges, including justices on the U.S. Supreme Court, did the same. And so did President Andrew Johnson.

Often, people used the phrase “officer of the United States”—the exact phrase used in Section 3—to describe the president. In an 1868 article on the impeachment of President Johnson, the editors of a Kentucky newspaper said that it was “accepted doctrine” that “the President of the United States is an officer of the United States.” When the editors took what they called a “raking shot” at this doctrine—positing that the president was not an officer of the United States because the president is elected, rather than appointed, to office—other news outlets promptly rejected their conclusion as “absurd.”

Trump doesn’t get into this evidence. Rather, he says that the “Constitution’s text”—meaning, the text written in 1787—and “structure” make clear that the president is not an “officer of the United States.” For example, he argues that the impeachment clause, which states that “the President, Vice President and all civil Officers of the United States” are subject to impeachment, implies that the president and vice president are not officers themselves. Trump portrays this as common sense: If the president were an officer, he argues, why would the Framers list the president and vice president separately?

Of course, Trump might be wrong as a matter of text. As some scholars suggest, the Framers may have listed the president and vice president separately because they were the most important officers subject to impeachment, not because presidents were categorically different from “officers of the United States.” Consider the verbiage of a 1776 letter to George Washington sending love to “Mrs. Washington and all the Ladies,” or a 2024 American Legislative Exchange Council proposal for “protecting Taylor Swift and all Americans from illegal deepfakes.” Was Martha Washington not a lady? And is Taylor—ahem, Miss Americana—not an American?

And even if Trump were right about the impeachment clause, he doesn’t present any evidence that the 14^th Amendment’s drafters and ratifiers incorporated the impeachment clause’s meaning when they used the phrase “officer … of the United States.” The Framers of Section 3 never said that they wanted to use the impeachment clause, or any other clause in the original Constitution, to define the words in Section 3. If they wanted the term to have a technical meaning drawn from another part of the Constitution, wouldn’t they have said so?

They didn’t. And as our brief shows, Section 3’s Framers used a variety of different phrases, rather than simply “officers of the United States,” to describe the people who would be disqualified by the provision. Some lawmakers abandoned the term “officer” entirely, instead stating that Section 3 would apply to “those men who have ever taken an oath to support the Constitution.”

And there is a lot of evidence that the generation of Americans who framed and ratified Section 3 intended to define “officers” broadly. As one federal judge said when charging a jury in a Section 3 case in Tennessee, “I charge you that [Section 3] includes all officers.” A North Carolina judge was similarly expansive in an 1869 decision, which emphasized that the amendment addressed anyone who took an oath to support the Constitution, from the “Governor” to the “Coroner,” to the “Inspectors of Flour.” Without evidence that anyone wanted to give “officers of the United States” a narrow meaning derived from a century before, the Supreme Court has made clear that the phrase’s meaning should be as Justice Antonin Scalia said in a 2008 guns case—the “normal and ordinary” one that it had at the time.

Trump’s efforts to do otherwise are surely self-serving. (Prominent conservative lawyer and retired Judge J. Michael Luttig, who filed a brief against Trump in this case, called Trump’s argument “the most simplistic and superficial argument of constitutional interpretation.”) But they are also a test for the Supreme Court’s justices, including the ones that former President Trump appointed, who claim to adhere to the ordinary public meaning of the Constitution. If original meaning matters, it should always matter, even when it leads to a result that some might find inconvenient.

For those justices who profess to care about the text and history of the Constitution, this case should be an easy one.