FORGET THE DEBATE over embryonic-stem-cell research. Never mind the saga of Chandra Levy and her creepy paramour, Gary Condit. This summer, the most fascinating — and revealing — proxy for the ongoing culture war that pits liberals against conservatives, libertines against moralists, and humanists against religionists is the glowering, portly visage of John Adams.

Until recently, the second president of the United States was an all-but-forgotten figure, his remarkable bust at Faneuil Hall leaving a more lasting impression than anything he ever said or did. But all that changed — first with the publication last fall of Joseph Ellis’s Founding Brothers: The Revolutionary Generation (Knopf), and then, far more spectacularly, with David McCullough’s best-selling epic biography, simply titled John Adams (Simon & Schuster).

Earlier this month, Publishers Weekly reported that more than a million copies of John Adams are now in print — a staggering figure for a serious work of history. John Adams is number one on the New York Times bestseller list, with Founding Brothers not far behind at number four. More significant, Adams himself has emerged as something of a blunt, straight-talking hero for our times.

Attendance at the Adams National Historic Park, in Quincy, has reportedly doubled. Congress appears likely to approve a monument to Adams, his wife Abigail, and their presidential son John Quincy. George W. Bush is said to be reading John Adams, presumably to learn how to avoid the mistakes that made John Quincy Adams an unpopular, one-term president. Mark Feeney, writing in the Boston Globe, compared the Adams phenomenon to the famous 1981 Rolling Stone cover line about Jim Morrison: he’s hot, he’s sexy, and he’s dead.

Yet this newfound admiration for Adams has prompted a surprisingly passionate backlash, not just against Adams himself, but against McCullough, who stands accused of producing " history lite, " a 751-page book devoted more to exalting Adams’s character and celebrating his and Abigail’s enduring marriage than to examining Adams’s sometimes loathsome policies and ideas. The most important of these critiques have come from Princeton University history professor Sean Wilentz, in a cover piece for the New Republic, who accuses McCullough of glossing over Adams’s flaws in order to write " nostalgic spectacle " and " pleasant uplift " in the mode of American Heritage magazine, where McCullough once worked; and from historian Richard N. Rosenfeld, in the new issue of Harper’s, who portrays Adams as a nearly demented monarchist, a bumptious, bumbling diplomat, a trampler of civil liberties, and even a bad father.

Nor has the debate over Adams been restricted to the relatively elite readership of the New Republic and Harper’s. Earlier this summer, Rosenfeld’s discovery that McCullough erred when he wrote that Thomas Jefferson had called Adams the " colossus of independence " was widely reported; a contrite McCullough responded that he would correct the mistake in subsequent editions. Then Globe political columnist Thomas Oliphant came out against an Adams memorial, citing Adams’s support for the notorious Alien and Sedition Acts of 1798, under which (among other depredations) editors who criticized President Adams found themselves imprisoned. The Adams boom also suffered a tangential setback when the Globe’s Walter Robinson reported that Joseph Ellis — whose earlier work on Adams, The Passionate Sage, McCullough has cited as an inspiration — had told his students at Mount Holyoke College, falsely, that he had served in the Vietnam War. (The college recently suspended Ellis for a year without pay.)

At root, though, this fight isn’t just about Adams, but rather about two competing visions of America. McCullough’s Adams is presented to us not just as a man worthy of admiration in his own right, but in contrast to Jefferson, his friend and rival. McCullough elevates Adams over Jefferson by dwelling almost exclusively on character rather than political philosophy (in an otherwise admiring review in Human Events, Lee Edwards writes that McCullough " is clearly less at home in the realm of ideas " ), a standard of judgment that favors Adams.

In the end, though, character can take a public figure only so far. As Wilentz writes, " Plenty of great Americans, after all, have had deeply flawed characters; and if sterling character were the main guide to greatness, all America would formally commemorate the birthday of Robert E. Lee instead of the birthday of Martin Luther King Jr. "