Even Jefferson Davis, leader of the Confederacy — and his lawyer — knew the insurrection clause in the U.S. Constitution not only disqualified him from holding office but, importantly, that Section III of the Fourteenth Amendment “executes itself” and once that constitutional Rubicon is crossed, disqualification was his “automatic” punishment.

This is one of several key arguments lifted straight from history that 25 prominent historians, professors, and legal scholars have presented to the U.S. Supreme Court in a new amicus brief supporting a December ruling from the Colorado Supreme Court finding that Donald Trump should be removed from the ballot for 2024 since he engaged in insurrection on Jan. 6, 2021, and is therefore ineligible for office.

Trump and his legal team contend — and they will argue this on Feb. 8 at the U.S. Supreme Court — that he did not engage in insurrection and that he is not technically an “officer of the United States,” as Section III defines it.

For roughly 40 pages, the amicus brief traverses centuries to expose lively, and often clear, congressional debate about the so-called insurrectionist clause and its understanding among senators, as well as its import in the impeachment of Andrew Johnson and how it came to force when it was time to reckon with one of America’s most famous insurrectionists: Jefferson Davis.

“Analysis of this evidence demonstrates that decision-makers crafted Section III to cover the President and to create an enduring check on insurrection, requiring no additional action from Congress,” the historians wrote this week.

The authors, who are renowned experts in the Civil War, Reconstruction era history, politics and law, elections, and more, say Section III was clearly meant to be broad in who it covered.

It did not simply or solely apply to former Confederates who wished to hold federal or state offices but rather, they write, it was an active “guard against corruption of government by anyone involved in future insurrections who had taken an oath to the U.S. Constitution.”

Pointing to Jefferson Davis and quoting Davis’ own lawyer at the time, the historians noted:

In seeking to quash his indictment for treason, Jefferson Davis argued that he was already punished through his automatic disqualification to hold public office under Section 3, which ‘executes itself … It needs no legislation on the part of Congress to give it effect.’

The government agreed but opposed quashing his indictment. Supreme Court Chief Justice Salmon Chase serving as circuit court judge, also agreed.”

Though the historians’ brief acknowledges that then-Chief Justice Salmon Chase later “seemed to take a different position,” they also emphasize that Chase’s ruling on Section III disqualification “required congressional action applied only to officials lawfully in office before the states ratified the 14th Amendment.”

“Statutory disqualifications, during the pendency of the Fourteenth Amendment in the states, did not require congressional action or court order. Yet they were essential for restoring loyal governments in the South, readmitting rebel states to the Union, and eradicating the Black Codes,” the amicus brief states.

When Johnson was impeached in 1868, decision-makers “explicitly recognized the President as a civil or constitutional officer of the United States” and, they noted, Johnson routinely described himself as the “chief executive officer of the United States.”

“Given that the President is subject to impeachment, he must hold an office of the United States, or the phrase ‘removal from Office, would have no meaning,” the brief states. “Similarly, the presidency must be one of the ‘offices of honor, trust, or profit under the United States,’ otherwise a convicted president could run for the presidency again. The terms ‘honor, trust, or profit’ add nothing to the term office; all federal offices, whether elected or appointed, convey honor, require trust, and are paid.”

The brief notes that two years before Johnson was impeached, a congressional debate unfolded between two senators of the time, Reverdy Johnson of Maryland and Lot Morrill of Maine. Sen. Johnson was an opponent of the Fourteenth Amendment and questioned its sponsors directly on why the language may seem to omit the president.

Morrill, an “influential backer of congressional reconstruction and the Fourteenth Amendment” corrected the senator.

“Let me call the Senator’s attention to the words ‘or hold any office civil or military under the United States,” the congressman said more than a century ago, records show.

In this week’s brief, the analysts say Johnson admitted the error and “no other Senator questioned whether Section III covered the president.”

Years later, as the Amnesty Act of 1872 came to fruition, similar debates played out on the record. Jefferson Davis was still alive — he would die in 1889 — and Section III, the historians wrote, “barred [him] from running for President of the United States, a disqualification amnesty would remove.”

A senator from Texas, James Flanagan, warned then that if Jefferson Davis “is living and ‘if the disabilities of Jefferson Davis were removed” that his base at the time, who were Democrats, would “go no further” than him to make him candidate for the presidency or vice presidency.

The brief also touches on the language of the oath a president takes when sworn in, vowing to “faithfully execute the Office of President of the United States, and will to the best of my ability, preserve, protect and defend the Constitution of the United States.”

The amicus brief notes: “The President’s constitutional oath does not include the word ‘support.’”

“However, the presidential oath represents the functional equivalent of support for the Constitution, in especially compelling terms: I ‘will to the best of my ability, preserve, protect and defend the Constitution of the United States,’” they argue.

When lawmakers debated the Fourteenth Amendment, no one in the U.S. Senate or House of Representatives tried to exclude the word “support” from their understanding of the oath.

“The oath requirement of Section 3 was supposed to apply broadly, and the word ‘support’ is not talismanic,” the historians wrote.

When the disqualification question first emerged, Law&Crime reported on similar analysis. The thrust of Section III comes from a well-rounded understanding of what informed lawmakers’ decisions as they reeled from the Civil War.

“This provision addresses insurrectionists who are engaging in behavior that violates the Constitution and the rule of law. Insurrections are inherently anti-democratic actions, so in some sense, this provision was concerned about anti-democratic behavior and authoritarian strongman behavior [so much] that it set up this lifetime ban on future office,” Praveen Fernandes, vice president of the Constitutional Accountability Center, said last year.

Trump was impeached for insurrection by the House, receiving the support then of just 10 House Republicans. He was acquitted by the Senate and now seems altogether poised to have the complete backing of the GOP as the 2024 party nominee despite his record of being the only former president criminally indicted as he faces 91 charges. Roughly a quarter of his charges are related to his alleged efforts so subvert the 2020 election.