The Problem of Democracy
By Nancy Isenberg & Andrew Burstein
543 pages, Viking, $35

John Adams, the second president of the United States, and his son John Quincy, the sixth, were ’two Peas parching in the Same fire’—ambitious for glory, but unwilling to court the fickle gods of popularity.

In the last week of his life, a small delegation of neighbors called upon John Adams at Peacefield, the ample country house in Quincy, Mass., that its owner had mockingly dubbed Montizello in contrast to the far grander mountaintop dwelling of Thomas Jefferson. His visitors encountered a palsied, toothless, half-blind figure, unable to rise from his favorite armchair to greet them. Yet Adams more than rose to the occasion when invited to supply a toast to be read at the town’s upcoming celebration commemorating 50 years since the Declaration of Independence redefined a patchwork quilt of British colonies as a sovereign nation.

“I will give you,” said the 90-year-old in a firm voice, “Independence forever!” His July 4 invocation might serve as a personal epitaph for this most paradoxical of patriots—a revolutionary who distrusted the mob; a New England provincial (“Boston town meetings and our Harvard College have set the universe in motion”) turned man of the world; and a plain-living farmer whose writings about “gentlemen” and “simple men” fueled charges of aristocratic pretense. Writing to James Madison in 1787, Jefferson called their Yankee contemporary “vain, irritable, and a bad calculator . . . of the motives which govern men.” For all that he considered Adams “as disinterested as the being which made him.”

While Jefferson became, in effect, the first party leader to occupy the White House, Adams, the nation’s second president (1797-1801), heeded George Washington’s warning about the “small but artful and enterprising minority” whose primary allegiance was to a political party. The same unyielding stance would characterize John Quincy Adams, our sixth president (1825-29). Like father, like son. “Never were two Peas parching in the Same fire more alike,” insisted the elder Adams.

It is easy to see why. Harvard-trained lawyers who risked their lives in the revolutionary cause, both Adamses rendered brilliant service to the fledgling United States. Each thirsted for reputation while refusing to court the fickle gods of popularity. Each married a remarkable woman who played an important part in his picaresque adventures. Each reached the top of the greasy pole, only to be evicted by more charismatic rivals: the first Adams losing to his erstwhile friend and vice president Thomas Jefferson; the second to the military hero and frontier champion Andrew Jackson. Compounding the sting of rejection, each man suffered the loss of a child to the Adams family scourge of alcoholism.

“The Problem of Democracy” is the first dual biography of the presidents Adams. Their entwined stories are told with authority and style by co-authors Andrew Burstein, a prolific historian of the early republic, and Nancy Isenberg, biographer of Aaron Burr and author of “White Trash” (2016), a pioneering examination of class in America. As ambitious as their protagonists, Mr. Burstein and Ms. Isenberg offer a frankly revisionist “lesson in myth busting,” portraying their subjects both as latter-day Ciceros and as victims of the “cult of personality” they blame for distorting modern-day elections as well as historical estimates of presidential performance.

Prickly and sometimes paranoid, incapable of the white lie or meaningless compliment, John Adams (1735-1826) is the modern political handler’s nightmare. “I do not Say when I became a Politician,” he once wrote to Benjamin Rush, “for that I never was.” Accepting him at his word, the authors reclassify Adams as a political scientist, one whose exhaustive study of his fellow men cured him of any illusions about human perfectibility. Likewise with American exceptionalism, if that term meant immunization from envy, greed, or the “passion for distinction” that this prolific diarist recognized in himself and the rest of mankind.

Refuting the familiar caricature of a curmudgeon hostile to the democratic impulse, the authors quote Adams’s “Thoughts on Government,” an influential text published in the spring of 1776. Here the future president gave pride of place in any Ciceronian “mixed government” to the “representative assembly”: “[It] should be in miniature, an exact portrait of the people at large. It should think, feel, reason, and act like them.” After the war a prescient Adams favorably contrasted the popularly elected House of Representatives with the Senate, the latter a cockpit of wealth and hereditary influence.

This made all the more ironic his campaign as vice president to promote quasi-royal titles—“His Highness, the President of the United States of America, and Protector of the Rights of the Same” comes to mind—as the prerequisite to institutional respect. By then extensive exposure to democratic uprisings in Europe and much closer to home had stoked Adams’s latent suspicions. “The multitude have always been credulous,” he concluded, “and the few are always artful.” It was to protect the multitude, and the American experiment deriving legitimacy from their consent, that Adams envisioned an executive as moral balance wheel—above politics, beyond factional intrigue.

His theories were put to the test as President Adams confronted a badly divided Federalist Party and an undeclared war with revolutionary France. From the sidelines Alexander Hamilton, panting for military glory, subverted the Washington administration holdovers who made up Adams’s cabinet. Not for the last time, a war scare imperiled civil liberties. Adams fathered the American navy. He also signed laws enabling the president to expel any foreigner deemed a threat to public safety, and jail any American convicted of publishing writings considered “false, scandalous, and malicious”—the original fake news.

At the same time Adams defied warmongers in his party by sending emissaries to talk peace with Napoleon and the French Consulate. His reward for averting war and holding a fragile Union together was defeat at the polls in 1800. “I have always been a Prophet of ill, and punished Accordingly,” ex-President Adams lamented to his son. In time he mellowed, becoming more reconciled to change than Jefferson, the disappointed utopian. Adams lived to see his namesake occupy the White House, though not long enough to observe the second Adams presidency fall victim to the same high-minded disdain for practical politics that had cut short the first.

“John has Genius,” his father said of John Quincy Adams (1767-1848), who was 8 years old at the time. Embarking on a diplomatic career at age 14, JQA’s fierce advocacy of American interests prompted a British rival to label him a bulldog among spaniels. Fluent in six languages, Adams taught rhetoric at Harvard, savoring a daily helping of Tacitus before breakfast. As James Monroe’s secretary of state, he pried Florida from Spain’s fading grip. In 1823 the bristling doctrine declaring the New World off limits to European intervention bore Monroe’s name but Adams’s assertive stamp.

On merit alone he cut a towering figure as Americans prepared to elect Monroe’s successor. That he would never win a popularity contest Adams readily acknowledged. “I am certainly not intentionally repulsive in my manners and Deportments,” he told his wife, Louisa, “but I have no powers of fascination—None of the honey which the profligate proverb says is the true fly-catcher.” Winning a disputed election in 1824 amid charges of a “corrupt bargain” making runner-up Henry Clay secretary of state, the second President Adams struggled to establish his legitimacy.

Frustrated in his diplomatic overtures, Adams enjoyed no more success with his sweeping program of internal improvements and economic planning. (This did not prevent one recent Adams biographer from lauding the “American visionary” for his far-sightedness.) Being ahead of one’s time may impress posterity; it is no advantage at the polls. By 1829, JQA was a prophet without office. Were he to identify with any political party, he later said, he would call himself a Constitutionalist. A party of one.

In our own time his reputation has risen, notably assisted by Steven Spielberg, whose 1997 film “Amistad” celebrated an elderly Congressman Adams for championing the right of petition and successfully arguing the Supreme Court case of several dozen Africans kidnapped by Spanish slave-captors. Admirers christened JQA “Old Man Eloquent”; Southerners angered by his antislavery views called him the “Madman From Massachusetts.” Crisply summarizing the Adamses’ legacy, the authors stress principle over partisanship. “Without endorsing democracy in ways that posterity would celebrate, they added to national prestige and power.”

It’s a fair assessment. So why don’t they loom larger in our collective memory? The authors blame it on voters who stress “hollow celebrity and contrived popularity” at the expense of “competence and rational judgment.” Worse yet, they argue, are the academic jurors who “stand to one side and wave the flag at a metaphysical parade of great presidents.” But history is not a zero-sum game. One can admire the public-spirited John Adams and his polyglot son while being unmoved by their bleak reading of human nature, just as we can draw inspiration from the self-evident truths of Thomas Jefferson while questioning the credentials of this Virginia slaveholder as a herald of liberty.

“To be an American is not to be someone,” writes Gordon S. Wood, “but to believe in something. And that something is what Jefferson declared.” The leaders we remember most favorably enlarge our expectations as they dispel our doubts. The presidents we call transformational—think Jackson, FDR, Reagan—earn their singular status because they change the political weather. They understand that presidential leadership is inseparable from political skill. It requires the deft manipulation of men and events, often from the wings.

Success in the Oval Office is realized through force of personality more often than spotlessness of character. None of which detracts from the presidents Adams, who compensate in integrity for whatever they lack in charm, and whose unblinking views of human nature remain as relevant to our imperfect democracy as they are unsettling.

—Mr. Smith, a historian and biographer, is working on a life of Gerald R. Ford.