Andrew Burstein and Nancy Isenberg are Professors of History at Louisiana State University and coauthors of "Madison and Jefferson." (Random House, 2010).

You’ll find lurking in every media-maximized sex scandal a man who feels himself in one way or another above the law.  Look up “smug” in the political dictionary, and if the first entry isn’t Herman Cain, it will probably say Newt Gingrich, who eagerly pursued Bill Clinton concerning morals charges that may have paled in comparison to his own contemporaneous straying problem.  Oops.

Now, let’s compare the other headline-grabbing sex shocker of the week: the concealment by Penn State University of Jerry Sandusky’s alleged fifteen-year rampage, in sexually abusing young boys.  There is a common thread between the sordid Sandusky business and Herman Cain’s outrageous behavior when confronted with charges of serial sexual harassment: Power and the belief in one’s invincibility make for a dangerous elixir.

The question that these stories of sexual misconduct raise is a peculiarly American one: Why do our people handle such episodes so badly?  The answer lies in the public’s inability to reconcile an admiration for powerful men and powerful institutions with its inevitable consequence of corruption.  Blind trust and unalloyed admiration create the atmosphere for abuses of power, for covering up misconduct, and even excusing it when it is revealed.

Herman Cain is merely the most recent in a long list of defiant politicians accused of sexual misconduct.  Abraham Lincoln didn’t live long enough for consorting with prostitutes to tar his reputation.  James Buchanan lived too soon to be presumed gay, though he pulled a Joe Paterno in protecting his close associate Dan Sickles, adulterous congressman and later Union general, who traveled to London on state business accompanied by his favorite prostitute....