As a presidential candidate, Hillary Clinton has a tight circle of advisers who counsel her on economic policy, foreign affairs and politics in general. In Sean Wilentz, she also has something of a house historian.

Wilentz, a Princeton professor, was an outspoken supporter of Clinton during her previous presidential bid, and has remained close to her since, according to Clinton insiders. He has been helping Clinton understand where and how her potential administration, and that of her husband Bill Clinton, fit into the arc of progressive history over the last half-century or more, according to people who know both him and the candidate. 

Wilentz, Princeton's George Henry Davis 1886 professor of American history, was a guest of honor at a Ready for Hillary event in the Hamptons, one Clinton source said, and remains in close touch with Clinton.

The role of Wilentz is noteworthy because of the political perspective he brings as an expert on President Andrew Jackson, considered the founder of the Democratic Party. Jackson was a relentless partisan and a populist, who attacked the aristocracy on behalf of the working class. (The white working class, that is; Jackson was also viciously racist and genocidal in his treatment of Native Americans.)

Wilentz, reached Tuesday in Germany, where he is teaching a course and working on a new book, declined to discuss his conversations with Clinton or her campaign. He said the best way to understand his current thinking on politics is to read his essay, "The Mirage," published in 2011 in The New Republic. ...