Exactly four centuries ago last Wednesday – on November 11, 1620 – the 41 men aboard the Mayflower signed a short document that was to become the Ur-text of American civil society. The passengers acted to keep the ship’s company from disintegrating into anarchy when they went ashore in Massachusetts, which was not the destination they had set out for. Accordingly, they cobbled together a quick pact before anyone disembarked, agreeing to remain united and work together.

What we know now as the Mayflower Compact, said the Harvard historian Samuel Eliot Morrison in a 1936 speech in New Hampshire, “was simply an agreement made by Englishmen who, finding themselves on English soil without any specified powers of government, agreed to govern themselves until the king’s pleasure should be signified.” That may indeed have been what the men “simply” agreed to. What their brief document came to represent, however, was nothing less than the birth of the American experiment.

We live in a time when the American experiment seems to be imploding amid polarizing partisanship and distrust. So this may be a good moment to look back 400 years and be reminded why the Mayflower Compact was so noteworthy.

I wrote about the Mayflower Compact and its significance in a column a few years ago:

Driven far off course by gales and rough seas as they crossed the Atlantic in the fall of 1620, the Mayflower ’s 102 passengers made landfall at a spot much farther north than they had planned. They anchored at the tip of Cape Cod in what is now Provincetown, hundreds of miles from the Virginia territory they’d been aiming for – and well beyond the jurisdiction of the Virginia Company of London, which had issued the patent authorizing them to build a settlement. It was a setback, but not enough to weaken the resolve of the ship’s Protestant Separatists, who had come to America to create a community true to their religious beliefs and who intended to stick together no matter what.

A majority of the Mayflower’s passengers, however, were non-Separatist “Strangers,” some of whom now insisted they were no longer bound by the original plan. William Bradford, who would emerge as the foremost Pilgrim leader, wrote that several Strangers began to make “discontented and mutinous speeches,” announcing that when the ship anchored they would go their own way. The Virginia patent was now void, they said, and “none had power to command them.”

Something had to be done to keep the group united. That something turned out to be the Mayflower Compact, the foundation stone of American democracy.

That may sound like an absurdly grand claim for a document barely 200 words long and improvised in haste. It contained no laws or blueprint for the governance of their new settlement. Some of those who signed were illiterate and made their mark with an “X.” Many of the signers would be dead within the year.

And yet the Mayflower Compact was something new under the sun. More than a jerry-built expedient to keep the group together, it established the first government in the New World based on the voluntary consent of the governed. Every free man on the ship was invited to sign – including those who in England, as mere uneducated laborers, would have had no political rights. Virtually all of them did so, forming what the Compact called “a civill body politick” with the power to elect leaders and make “just and equall lawes, ordinances, acts, constitutions, and offices” for the general good of the colony.

To be sure, the signers professed their loyalty to “our dread soveraigne Lord, King James.” But they claimed authority to rule themselves not in the king’s name, but from their own free will. The agreement they signed off Provincetown Harbor declared their intention to “covenant and combine our selves together” for the purpose of self-government. When each man “promise[d] all due submission and obedience,” it was to the colony they were poised to launch in America – not to the throne back in London.

Morrison might tell his New Hampshire audience that the Mayflower Compact was “simply” an agreement to work together, but John Quincy Adams knew better. He regarded what the Mayflower passengers accomplished with something approaching awe. Their shipboard agreement, he said in his Forefathers’ Day address in 1802 , “is, perhaps, the only instance in human history of that positive, original social compact which speculative philosophers have imagined as the only legitimate source of government.” What Locke and Rousseau would theorize about, Adams argued, the men on the Mayflower had actually done: “Here was a unanimous and personal assent, by all the individuals of the community, to the association by which they became a nation.”

They underscored that the right of free people to govern themselves came from God, who is mentioned four times in the brief document.

That wasn’t all they did. They underscored that the right of free people to govern themselves came from God, who is mentioned four times in the brief document. The Compact’s opening words are “In the name of God, Amen.” Its core purpose, the forming of a body politic, is expressly undertaken “solemnly and mutually in the presence of God.”

Yet if the Mayflower Compact was explicitly religious, it was not sectarian. It contains no reference to a church. It was signed by no clergyman, for there was none aboard. It contained no Separatist doctrine. There was nothing in it that a mainstream member of the Church of England, or even a Roman Catholic, could have objected to.

Thus, in just 200 words, were sown the great themes of American democracy: that all men are created equal, that they are endowed by their creator with basic rights, that government derives legitimacy from the consent of the governed. In 1776 – a century and a half later – those themes would be enshrined in the American Declaration of Independence. But it was in 1620 that those ideas had their birth, when a tiny band of Pilgrims, about to step ashore into a wintry Massachusetts wilderness, set them down in writing, and agreed to live together as fellow citizens.

Ours is not the first society to be riven by deep disagreement; the Mayflower’s passengers were, too. They found a way to surmount their quarrels and to bind themselves to each other in a spirit of respectful liberty and equality.

Shouldn’t we be able to as well?

This op-ed originally appeared in “Arguable,” a weekly newsletter written by Boston Globe columnist Jeff Jacoby.