Sexual fidelity has had a dark side for the Democratic presidents of the last century because marital loyalty is strongly correlated with serving just one term as president.  

Franklin D. Roosevelt continued his affair with Lucy Mercer during his presidency and was re-elected three times.  Harry S. Truman was a faithful husband but was only elected once.  John F. Kennedy had many affairs during his presidency and would surely have had an excellent chance to be re-elected to a second term had he lived.  Jimmy Carter was faithful but was only elected to one term.  Bill Clinton was elected to two terms and was sexually involved with Monica Lewinsky during his presidency.  Essentially, in the last century or so, those Democratic presidents who do not experience extramarital sex while in office are elected to only one term, whereas those who have such an experience serve multiple terms. What could account for this pattern? 

One hypothesis is that a president without a time-consuming extracurricular relationship has more energy to concentrate on his priorities and to articulate his vision for the country's future. This type of person would convey his programs thoroughly enough by the end of his initial term for the electorate to reject him!  Also, martially-unfaithful presidents might be likely to speak less directly than do faithful ones; the less faithful could be more adept at hiding their true feelings.  This opaque manner of speech could permeate the rest of their lives.  Roosevelt was notorious for never allowing his closest advisors know which side of an issue he supported, whereas monogamous Truman was known for his directness.

President Obama can up his chance of re-election by acquiring a mistress.  Given the extreme strategies that politicians have implemented during elections, why not?

Peter Landesman (mathmaze@yahoo.com) is a teacher, a mathematician and an author of the 3D-maze book Spacemazes, with which children can have fun while learning mathematics.