Michael Beschloss, a presidential historian and author of nine books, is currently writing a history of wartime presidential leadership.

When John F. Kennedy was elected president in 1960, some alert political observers scrutinized the books written by historian Arthur Schlesinger Jr., then at Harvard, for clues that might reveal what to expect once JFK was in power. Schlesinger was also sensitive to the impact that historical ideas might have on a presidency. He was not displeased when his landmark early work “The Age of Jackson” (1945) was exalted as rationale for the domestic liberal activism of Franklin Roosevelt and Harry Truman. And when Truman was widely vilified for firing Gen. Douglas MacArthur in 1951, the commander in chief was delighted when Schlesinger came to his defense by writing a book, with New Yorker contributor Richard Rovere, called “The General and the President.” While running for president, Kennedy let it be known how much he admired Schlesinger’s three-volume history of the early FDR years, and, after his victory, he appointed the historian to his White House staff.

Sean Wilentz of Princeton is one of the best American historians of his generation. He and Hillary and Bill Clinton are well known to be strong mutual admirers. There is no particular reason to suspect that Wilentz aspires, as Schlesinger did, to enter the federal government. Should Hillary Clinton be elected this November, however, one would do well to revisit Wilentz’s work for a preview of some of the historical rationale that might be deployed by the new president, explicitly or otherwise, in defense of her agenda and approach. For instance, Wilentz’s affinity for happy political combat on behalf of left-of-center goals is consonant with the former secretary of state’s presidential announcement speech a year ago this month. In her remarks, delivered at a rally in New York’s Four Freedoms Park, honoring Franklin Roosevelt, she called her program the “Four Fights.”

Wilentz is by no means a Bernie Sanders Democrat. When Bill Clinton was in the White House, the historian defended the president against charges that he was insufficiently liberal and got him to give the keynote address at a 2000 Princeton conference on the history of progressivism, for which Wilentz also persuaded Schlesinger to deliver a paper. Both Wilentz and Schlesinger testified before Congress in Clinton’s defense during the House Judiciary Committee’s impeachment hearings in 1998. Wilentz has reportedly been in contact with Hillary Clinton during the current campaign.

For those readers eager to be introduced to Wilentz’s work, “The Politicians & the Egalitarians” is a good place to start. Preponderantly drawn from Wilentz’s writing for journals including the New York Review of Books and the New Republic, the book suggests the range of the author’s interests and his command of more than two centuries of American history, addressing W.E.B. Du Bois, the Gilded Age, Lyndon Johnson, Thomas Paine, Thomas Jefferson, John Quincy Adams and Abraham Lincoln. Not surprisingly, he chides Lincoln historians for being overinclined to scoff at “the importance of party politics” in his ascent, noting that “the candor of Lincoln’s language, the ease with which he accurately describes his real vocation, is bracing. He saw no shame in the practice of politics, and experienced no priggish discomfort about what it takes to get great things done.”

"The Politicians and the Egalitarians: The Hidden History of American Politics" by Sean Wilentz (Norton)

In the heart of this book, Wilentz marvels that the national effort to reduce “economic inequality and the privilege exercised by a plutocratic few” became so notably quiescent during the decades between roughly the early 1970s and the Great Recession of 2008. That effort, as Wilentz relates, has been one of the most abiding forms of American political activism. Describing the origins of the egalitarian tradition, he notes that early “free Americans did not live in the classless utopia described by some patriots and some astonished foreign visitors, but they could easily consider America the closest thing in history to such a utopia, so long as they deemed dark-skinned slaves and Indians inferior castes outside society.” He recalls that by 1928, the top 1 percent of the nation’s households owned more than half of America’s wealth and that the period from the early New Deal to the 1970s — with the towering exception of the long postponement by both parties of serious action on civil rights — saw “the sharpest and most profound reduction in economic inequality in all of American history.”

Then, with Ronald Reagan, came what Wilentz describes as the most powerful “demonization” of government since Reconstruction, accompanied by a large increase in the income accruing to the haves at the top of American society. He credits Bill Clinton with being “able to outfox” the “increasingly radical” Republicans in Congress during the mid-1990s by using those powers available to a president to “reverse the trend toward inequality, overseeing dramatic decreases in unemployment and increases in real wages.”

In the spring of 2008, as a champion of Hillary Clinton’s first presidential candidacy, Wilentz repeatedly upbraided her Democratic primary opponent, Barack Obama. For instance, in February 2008, he wrote in the New Republic about the “gap” he found between the senator’s “promises of a pure, soul-cleansing ‘new’ politics and the calculated, deeply dishonest conduct of his actually-existing campaign.” In his new book, Wilentz elaborates, in retrospect, on one of the central reasons for his position by tracing the history of what he calls “the American dream of politics without conflict, and of politics without political parties,” from the time of George Washington to that of Obama, who, he says, won power by “promising not simply to unite the country but to transcend partisanship, substituting a spirit of thoughtfulness, expertise, and integrity above party and politics.”

Illuminating one of the dividing lines that now separates some of Obama’s most fervent admirers from those of both Clintons, Wilentz argues that, after achieving “historic health care reform” and an economic stimulus, it was only in 2015, after withstanding four years of an opposition Congress and failing to make a “grand bargain” with the other side, that Obama shed his “postpartisan illusion” to circumvent the House and Senate by vigorous use of executive orders.

Wilentz goes on to insist that throughout history, such “antidemocratic” allergy to political conflict — which, he pointedly notes, was not shared by modern presidents such as Woodrow Wilson, Roosevelt, Truman, Kennedy, Johnson, Richard Nixon, Reagan or Clinton — “invariably ensured ultimate political defeat and even catastrophe, no matter whether the cause being advanced came from the right or the left,” and that every “fundamental reform” in American life “has involved partisan politicians advancing basic and far-reaching political principles.”

Should Hillary Clinton take office next year, it is not at all impossible that we will hear the new president espousing this approach to executive power.

The Politicians & the Egalitarians
The Hidden History of American Politics

By Sean Wilentz

Norton. 364 pp. $28.95