State courts in Colorado, Michigan, Minnesota and elsewhere have so far declined to rule in favor of challenges asserting that Donald Trump should be disqualified from holding the presidency again under Section 3 of the 14th Amendment. (Cases in Michigan and Colorado have been appealed.)

Challengers assert that Mr. Trump is barred because, as stated in Section 3, he was an officer of the United States who, after taking an oath to support the Constitution, “engaged in insurrection or rebellion against” the country, or gave “aid or comfort to the enemies thereof,” before and during the Jan. 6, 2021, attack on the Capitol.

Mr. Trump and his campaign have called this claim an “absurd conspiracy theory” and efforts to bar him “election interference.” Some election officials and legal scholars — many of them otherwise opposed to the former president — have also been critical of the efforts.

The Georgia secretary of state, Brad Raffensperger, writes that invoking Section 3 “is merely the newest way of attempting to short-circuit the ballot box.” Michael McConnell, a former judge and professor at Stanford Law School, claims that keeping Mr. Trump off the ballot on grounds that are “debatable at best is not something that will be regarded as legitimate.”

These criticisms fail to adequately grapple with why Republicans insisted on placing Section 3 of the 14th Amendment in the Constitution after the Civil War in the first place. Despite the provision’s rare appearance for the past 150 years, the issues disqualification raises today remain vibrant and even critical to preserving our democracy.

For the Republicans who framed and ratified the 14th Amendment, Section 3 was a vital means for promoting and protecting democracy by preventing proponents of political violence from disenfranchising voters. Since the Civil War, we have rarely faced something like the national trauma of Jan. 6 and the efforts to overturn the 2020 election and thus disenfranchise millions of Americans. In other words, that provision’s 150-year absence from national discourse is a consequence of normal politics, not a failure to apply the Constitution in an appropriate circumstance.

But Section 3 is one tool we have to determine the integrity of Mr. Trump’s current bid. Working through the possibility of constitutional disqualification applies our Constitution’s understanding of democracy, and the nation will know if Mr. Trump is qualified to run for the presidency again.

In the view of many of those who argue against the use of Section 3 today, Mr. Trump should not be subject to constitutional disqualification unless he did something like firebomb the Congress. Otherwise, they maintain, adhering to constitutional rules would disenfranchise Trump voters in ways that might lead to political violence.

Post-Civil War Republicans were familiar with these claims. Supporters of slavery and white supremacy in 1866 complained about disenfranchisement and stoked fears of political violence when members of the 39th Congress debated Section 3. Democrats and a few very conservative Republicans claimed that white Southerners should not be deprived of the opportunity to vote for Confederate leaders.

Senator James Guthrie of Kentucky said that the people disqualified from office had “the confidence of the people of that section of the country.” Opponents of the 14th Amendment claimed that civil war might be renewed if traitors were not given their fair chance to hold elective office. Senator Edgar Cowan of Pennsylvania stated that Section 3 would “sow the seeds of another rebellion.”

Republicans during Reconstruction scorned white supremacists who invoked democratic principles only on behalf of themselves and threatened violence should their demands not be satisfied. Representative Thaddeus Stevens warned Republicans that unless the majority party altered the structure of constitutional politics by constitutional amendment, “the House will be filled with yelling secessionists and hissing copperheads.”

Government by former Confederates and their political allies would allow the fruits of the Union victory in the Civil War to rot and the 13th Amendment to become a parchment barrier. Republicans maintained that people who had taken an oath to support the Constitution and then engaged in insurrection or rebellion could not be trusted with future office.

The constitutional disqualification of government officials who violated their oath of office was central to the 14th Amendment’s goal of ensuring government by people who could be trusted to be faithful to the Constitution, maintain majority rule and have the character necessary to hold public office.

The constitutional oath of office is tightly connected to disqualification for engaging in insurrection. Nineteenth-century Americans understood an insurrection as an assemblage attempting to resist the implementation of law by force or violence for a public purpose. So understood, Section 3 does not apply to past and present government officials who vigorously champion constitutional reform, even those who abolish constitutional democracy or repeal fundamental human rights.

The past and present officers Section 3 would bar are those who sought to subvert by violence the Republican commitment to racial equality, as racial equality was understood in the 1866, and free labor (the view that society should be governed by voluntary contract, not on status, at least for men).

Republicans during Reconstruction understood Section 3 as an enfranchising device that enabled voters rather than mobs to determine the course of constitutional politics. The past and present officeholders who led the South into secession were disenfranchising the citizens who voted for Abraham Lincoln and his commitment to placing slavery on a “course of ultimate extinction.”

Political decisions not to proceed with Section 3 disqualifications for fear of violence would undermine the central goal of that constitutional reform. No political leader, from Jefferson Davis to Donald Trump, in the view of those responsible for the 14th Amendment, should have his path to public office smoothed by the threat of violence should the laws be enforced.

Decisions disqualifying Mr. Trump or any other insurrectionist from public office disenfranchise no voter. Trump supporters remain free to vote for any candidate who champions the mix of policies Mr. Trump champions.

Disqualification merely prevents voters from choosing candidates who, when they or their proposals are defeated by democratic vote, would take to the streets, or support those who do so, to reverse by violence what they could not achieve through persuasion.

As shown following the Amnesty Act of 1872, the effects of granting amnesty to former Confederates should caution those too willing to provide practical or legal amnesty to Mr. Trump today. The 1872 act permitted most people who violated their oaths of allegiance during the Civil War to resume state and federal office holding. Many were elected or appointed.

The result was decades of Jim Crow, disenfranchisement and campaigns of terror against people of color that state officials either joined or ignored.

The public evidence assembled by the select committee to investigate the Jan. 6 attack on the Capitol that “rioters were inside the halls of Congress because the head of the executive branch of our government, the then-president of the United States, told them to attack” strongly suggests that Mr. Trump should be disqualified from presidential ballots. The judge in the Colorado case, Sarah Wallace, actually ruled that Mr. Trump engaged in insurrection against the Constitution. (She rejected his disqualification on the dubious technicality that Section 3 applies to every federal officer excepting a president who has never held any other public office.)

But whether constitutional disqualification is warranted should be determined by law and not by fears of political inconvenience and disruptions.

Section 3 compels Americans to resist political leaders who have a history of promoting violence as a means of achieving political goals, even when that leader is popular and his supporters armed.