There are many possible factors: a need to express power, a love of conquest, perhaps narcissism — all characteristics that may serve a politician well in other arenas. But in my view the factor most responsible for philandering in public officials is a predisposition for risk-taking, which also happens to be an essential quality for politicians. My label for it is the “Type T personality,” with the “T” standing for thrill.

Being a Type T doesn’t have to be a problem: Many of America’s great successes and achievements couldn’t have happened without risk-takers. The nation was founded by Type T men who weren’t afraid to rise up against one of the world’s great empires. I believe the United States can be characterized to some extent as a Type T nation, tilting in the risk-taking direction. But Type T individuals may also be prone to negative types of risk-taking, including crime, drug use or sexual encounters that end badly…

Why might we expect risk-takers to be attracted to leadership roles in politics? Analyze the job. It’s unpredictable. A candidate can pour everything he or she has into a campaign and still lose. There is no tenure, no 9-to-5 schedule, and constant travel. A politician always has to be on, and be comfortable meeting a constant stream of new people and speaking extemporaneously in public. There is no proven playbook for success. A politician also lives a fishbowl life, with little privacy. Every day, there are decisions to be made that can make or break a career. Maintaining a normal home, family and marital life is nearly impossible. Who can not only accept but thrive in such circumstances? Risk-takers.