There may be no more difficult task than trying to rate American presidents; no sooner has history made a decision on Thomas Jefferson, Ulysses S. Grant or Harry Truman than a current event changes our perception of a past one and the perceptions of the presidents shift all over again.

With this truth firmly in mind, Robert Merry, editor of the National Interest, has undertaken the ranking of our chief executives through a new method -- or rather, through an old one, examining them in the light (or perhaps taillight) of how they stood in their own time. "I seek to analyze the presidency," Merry writes in his introduction, "through an intertwined exploration of both the academic polls and the ballot box reactions."

Merry doesn't place much stock "in the personal judgments of individual analysts or commentators (including myself) except in so far as they contribute to the ongoing Rating Game discussion." This approach," he says, "militates against any tendency to insert partisan sentiments into the discussion.

Would that that were true. But for the most part, "Where They Stand: The American Presidents in the Eyes of Voters and Historians" is both stimulating and refreshing, particularly in its take on presidents such as Andrew Jackson, James K. Polk and Ulysses S. Grant, whose legacies have been obscured by time and controversy.

Jackson, for instance: "No man of his time," wrote Arthur Schelsinger Jr. in 1989, "was at once so widely loved and so deeply hated." Still, Jackson made an indelible impact on U.S. history. He opened up American politics and moved the country a considerable distance toward democratic ideals. James Madison was "generally considered a middling president," but gets high marks from Merry for "his high standing with his fellow citizens at the time of his ascendancy."

Polk's "tenacity and political adroitness extended the country's territorial expanse by a third and established America as a transcontinental power." Unfortunately, he failed to convey his message to voters and was not re-elected. Ulysses S. Grant really gets a boost, pulled out of the "Failure category."

"Where They Stand," though, stumbles on analysis of contemporary presidents. Jimmy Carter's administration was a failure by most standards, but it would look less so if Merry had mentioned his primary accomplishment, the Camp David Accords. And Merry seems to be trying to pull George W. Bush from the bottom of the presidential list into middle-ground territory, failing to acknowledge his inept handling of the events following Hurricane Katrina and, most glaringly, the financial collapse of 2008. Likewise, in his rather gloomy projections for Barack Obama, he fails to stress the deep holes the economic disaster and Bush's war in Iraq left him in.

"Where They Stand" is, often, first-rate history, whatever its shortcomings on current affairs.

Allen Barra writes for the Wall Street Journal and American History magazine.