By Meghan Cox Gurdon

"What are the odds?" we ask when strange things occur. What, for instance, are the odds that the two principal architects of the Declaration of Independence would both die on the Fourth of July, exactly 50 years after the Second Continental Congress adopted the document?

The odds are so poor that probably no one would take that bet. Yet the thing happened. On Independence Day 1826, John Adams and Thomas Jefferson — former presidents who had been great friends, then bitter enemies, then friends again — shuffled off their mortal coils within hours of each other.

Jim Rasenberger tells the story of this amazing case of synchronicity in "A Perfect Coincidence," a thick tome with a sober cover that gives every indication of being a "dad book" — probably not much fun and of interest chiefly to history buffs. Well, surprise! This book is a delight, a sparkling work of narrative nonfiction that acquaints the general reader with the thoughts and doings of two giants of American democracy, brilliant weirdos both, while also telling the story of the founding of the fractious country that Adams and Jefferson loved so well.

Mr. Rasenberger, whose previous books include "America 1908" (2007) and "Revolver" (2020), employs a framing device that exemplifies his humane, good-natured and judicious approach to the past. He asks us to imagine the Eye of Providence looking down on America on the night that Adams and Jefferson were dying.

"You didn't have to believe in Divine Providence — and don't now — to appreciate the role it played in early American history," he notes, explaining that "even the most deistic and unorthodox" of the revolutionary generation saw the hand of the Almighty moving in American affairs. With narrative deftness, Mr. Rasenberger causes his speculative Eye to roam over a "prosperous and kinetic land," in the process acquainting us with the contours of the U.S. half a century after it came to be. Then the Eye takes in the plight, in 1826, of those whose liberty would take generations to secure. "If you believed in Divine Providence, as most Americans did," the author writes, "you knew that slavery, sooner or later, was going to tear America apart."

Throughout the book, Mr. Rasenberger never loses sight of the tormented double nature of the early American experiment — bondage in the land of the free — nor does he seek to sink one with the other. Like the calm, godly Eye, he registers the good and bad of human nature with moral clarity but without castigation. He conveys the grief and terror felt by abolitionists in the founding generation, who predicted catastrophe, and the abhorrence of the institution among such men as Adams, who believed in emancipation by gradual means. The author also explores the sleight of intellect practiced by Jefferson, a slave owner who deplored slavery and used his rhetorical skills to cast the cause of states' rights as a question of liberty. "The beauty of this narrative was that it not only absolved Jefferson and his fellow slaveholders of their sins; it absolved America as a whole," Mr. Rasenberger writes. "As long as the focus was on the noble good of liberty, the blight of slavery could be accepted or ignored, at least by some people, and at least for a time."

In the greater historical scheme, the phrase "a perfect coincidence," used by Jefferson in an 1812 letter to the patriot Benjamin Rush, originally described the alignment of his ideas with Adams's and the harmony of their efforts to bring about (and in Jefferson's case to write) a Declaration of Independence that would mark the repudiation of Great Britain by America's 13 colonies.

The two men, dubbed by their mutual friend Rush "the North and South Poles of the American revolution," made an odd pair. Adams was a balding curmudgeon from Massachusetts — brainy, argumentative and physically ill-favored. (In his own words: "short thick fat.") Jefferson was a suave Virginian — rich, genteel, handsome, with a charming manner and a polymathic mind.

The two men are believed to have met in Philadelphia in the late spring of 1775, when Adams was pushing his fellow delegates to the Second Continental Congress to declare independence from Great Britain. It is easy today for us to forget what a risk the country's Founders were taking when (with the help of Jefferson's graceful pen) they broke with King George III. Revolt against the crown was treason, and treason brought horrific punishment: Strangling, disembowelment while alive, decapitation and quartering. It took courage for these men to act as they did. It also took visionary genius, when few republics had existed (or lasted) anywhere, for Adams to have contrived a plan to establish a government of checks and balances; of laws, not men.

A movie pitch of the Adams-Jefferson relationship might go like this: Two mismatched American patriots collaborate on the Declaration of Independence, then get diplomatic jobs in Europe and become besties. On their return to the U.S., things get ugly. The fat one becomes president and the good-looking one, the runner-up, trashes his friend behind his back. By the next election, they're enemies. The good-looking one wins the White House. For a decade, they hate each other. In old age, their hearts soften. They start writing to each other again. On the semicentennial Fourth of July, having reconciled, both men die.

So, you ask, what are the odds? According to a calculation cited by Mr. Rasenberger, the chances of such a thing taking place are approximately 1.72 billion to 1. People at the time truly thought this was the work of Divine Providence. (Mind you, five years later, in 1831, James Monroe became the third ex-president to die on the Fourth of July, but that is another story for another time.)

  • Mrs. Gurdon is a Free Expression columnist at WSJ Opinion and the author of "The Enchanted Hour."