All other issues to one side, when a leading presidential candidate, an alum of the Ivy League, insists that an amendment to the United States constitution doesn’t say what it clearly does say, it’s well past time the country sat down and had a little chat about its founding charter. While Donald Trump’s attack on the 14th Amendment is stupid and deranged, and his allegedly moderate Republican opponents’ tongue-tied responses abominable, the mop-topped Muppet is actually on to an important fact about the role of the Constitution in 21st-century American life. Democrats and other gauchistes ignore it at their peril. It is this: We have come to rely too much on the 14th Amendment for ensuring a free and just society.

The importance of the 14th Amendment has always been as misunderstood as it has been profound. In July 1868, when the amendment was finally ratified by the states, The Nation commented that it had “been so long before the people that the average reader has very likely forgotten just what it is.” As the recent idiocies have shown, that is only more true now.

The past is always a foreign country, but the United States before the ratification of the 14th Amendment in 1868 was truly a different land. They did things differently there. The Constitution’s endorsement of slavery had just been rescinded by the 13th Amendment, ratified by the states 150 years ago this December, but the Supreme Court’s decision in the fugitive-slave case Dred Scott still stood, stating that the millions Americans of African descent were not and could never be citizens of the country of their birth. No other firm definition of citizenship previously existed. With millions of former slaves loosed upon the country, some provision for their legal status had to be made.

There were other motivating factors behind the amendment. Because slaves had been freed but not given the vote and the Constitution’s notorious three-fifths formula for congressional representation remained intact, the Southern states were poised to return to Congress after the Civil War even stronger than they had been before Abraham Lincoln was elected president and they left the Union. Former slaves would now count as full persons for the purposes of apportionment, even though they still couldn’t vote. As I wrote last winter in a piece about the long-forgotten voting-rights clause in the 14th Amendment, “The successful campaign to abolish slavery would have the effect of significantly increasing the slave states’ power in Congress, perhaps to the point of allowing them to restore their ‘peculiar institution,’ in effect if not in name.”

The whole purpose of the amendment,  Thaddeus Stevens said as Congress began the process of drafting it, was “to render our republican government firm and stable.”

Stevens returned again and again to this metaphor of solid physical construction. When Congress finally passed the Amendment in the spring of 1866 and sent it to the states for ratification, the aged Stevens, the most effective radical politician this country has ever seen, delivered an emotional speech to the House.

“In rebuilding,” Stevens observed, “it is necessary to clear away the rotten and defective portions of the old foundations, and to sink deep and found the repaired edifice upon the firm foundation of eternal justice.”

“New Foundation may not come tripping off the tongue quite as easily as New Deal,” Peter Baker of The New York Times observed in the spring of 2009, shortly after President Obama used the phrase eight times in a single speech on the economy. But perhaps the former constitutional lawyer’s misfired attempt at an administration-defining catchphrase was, in fact, a subtle reference to Stevens: a new foundation is precisely what the 14th Amendment was, and a century and a half later, it is what we need again.

* * *

From the rights to gay marriage to abortion, from birthright citizenship—as Eric Foner writes in the next issue of The Nation, our chief claim to genuine American exceptionalism—to the guarantees of the civil-rights acts of the 1950s and 1960s, so much of what progressives value about the United States in the 21st century finds its constitutional source in the 14th Amendment. It achieved the enshrinement of egalitarian principles in a document that only a few decades earlier the abolitionist William Lloyd Garrison had famously denounced as “the most bloody and heaven-daring arrangement ever made by men for the continuance and protection of a system of the most atrocious villany ever exhibited on earth.” It was the high-water mark of political influence for the American freedom struggle.

In the winter and spring of 1866, as they labored to write and then pass the 14th Amendment, Thaddeus Stevens and his fellow Radical Republicans did the political heavy lifting that has allowed freedom and justice to thrive in the United States to whatever, often limited, extent it has. They are the underwriters of American progress.

Yet at a time when Thaddeus Stevens’s former party is currently represented best by a textbook fascist demagogue, perhaps it is worth pausing to reflect: How healthy is it to found a democratic society on a single section, however enlightened, in a document otherwise riddled throughout with vague riddles and obsolete obscurities, one which welcomes—like its former interpreter, the current president—any reading one chooses to project onto it?

Even Thaddeus Stevens, in his speech about the passage of the 14th Amendment in 1866, recognized that it was only a temporary solution to the problems inherent in the United States Constitution, and that egalitarians of his ilk would, in the future, have to come up with their own solutions. To skeptics who argued the amendment did not, in fact, go far enough toward ensuring freedom and equality for all Americans, Stevens replied, “It would not be wise to prevent the raising of the structure because some corner of it might be founded upon materials subject to the inevitable laws of mortal decay. It were better to shelter the household and trust to the advancing progress of a higher morality and a purer and more intelligent principle to underpin the defective corner.”

After 150 years, the structure of American democracy has suffered more than a little from “the inevitable laws of mortal decay.” It is past time to begin new. This is what Reconstruction was, and what it will have to be again.

Donald Trump, alas, is not quite the herald of “the advancing progress of a higher morality.” Maybe Bernie Sanders is?