The Mayflower had a harrowing two months crossing the Atlantic. Its mast splintered in rough water and two people died, as supplies dwindled and passengers grew sick. It arrived in the New World later than expected, on the cusp of a punishing winter.

It was this voyage, of course, that gave us one of the foundational documents in our history, the Mayflower Compact. It is easy to forget that the Compact, the first artifact of American self-government, was written at the outset of a survival challenge worthy of the TV show “Naked and Afraid,” except the stakes were real.

In his excellent history of the Mayflower and the initial settlement at Plymouth, Nathaniel Philbrick writes of the outlandishness of the Pilgrim project. The Pilgrims rejected what they considered a corrupted Church of England and wanted to found their own community, but might as well have resolved to do it on the far side of the moon.

As Philbrick notes, all other ventures to create permanent English settlements in this hemisphere had failed, with the exception of Jamestown, which wasn’t exactly an encouraging precedent. Its first year, 70 of 108 people died, and the next year, in the course of a brutal six months, another 440 of 500 settlers perished.

Against these odds, the Mayflower traversed the Atlantic and was immediately confronted with what political philosophers might call a crisis of the regime. It sighted land off of Cape Cod on Nov. 9, 1620, well north of its intended destination in Virginia. It was too dangerous to venture farther down the coast. So, its passengers would have to land in Massachusetts, even though no legal provision had been made to do so. What was the governing authority in this literally uncharted territory?

An argument ensued. In the words of the eventual governor of Plymouth Colony, William Bradford, some passengers made “discontented and mutinous speeches,” and threatened to go their own way, because “none had power to command them.” (The passengers were divided between the Pilgrims — highly motivated, closely knit believers on a mission — and others who were on board simply to increase the odds of success, the so-called Strangers.)

This created a truly ruinous prospect. Divided, everyone might well die. An agreement was hammered out and signed by the men on the ship. It provided that they would “covenant and combine ourselves together into a civil body politic.” The compact would be “for our better ordering,” and “to enact, constitute and frame such just and equal laws, ordinances, acts, constitutions and offices, from time to time, as shall be thought most meet and convenient for the general good of the Colony.”

This wasn’t a revolutionary statement. It acknowledged “our dread sovereign Lord, King James.” The Pilgrims, of course, didn’t intend to set in motion the process that would create a liberal democracy. Historian Walter McDougall calls Massachusetts “an oligarchy of the devout.” And the Compact doesn’t set out any explicit rights.

Yet the implication is clear. As political philosopher Willmoore Kendall put it, “The Compact is itself an exercise in freedom, and a tacit assertion of at least one right, that is, the right to be free, the right to make such a compact as the signers are making.”

“Here,” John Adams marveled, “was a unanimous and personal assent by all the individuals of the community, to the association by which they became a nation” — and in the most isolated, trying circumstances imaginable.

Half the settlers died during the ensuing winter, “sometimes two or three of a day,” according to Bradford. But they persevered, and their ranks were steadily increased by subsequent waves of settlers. William Bradford was re-elected 30 times as governor of the colony (for one-year terms), and a through line runs from the Mayflower Compact to our contemporary democracy that hasn’t lost its vitality or ability to surprise.

For that, and the wisdom and endurance of our forebears, we all should be grateful.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.