So, Los Angeles Mayor Antonio Villaraigosa cheated on his wife, making him eligible for membership in the Politicians Infidelity Club. There are lots of members including sitting and former big city mayors -- San Francisco’s Gavin Newsom, San Antonio’s Henry Cisneros, and New York’s Rudy Giuliani.

But why should we care?

Not that long ago, politicians could reasonably expect that their private lives would remain private. With some exceptions, journalists and political opponents followed an unwritten rule that private conduct was off limits.

That’s why few Americans knew that President Franklin Roosevelt was wheelchair-bound, let alone that he was probably having a long-term affair with his wife’s social secretary. This code of silence also protected countless others, including President John F. Kennedy and Martin Luther King, Jr.

This changed in 1987 when presidential candidate Gary Hart was caught cavorting with a young model on a yacht named, appropriately, Monkey Business. The affair scuttled both his campaign and his career. More important, it was the turning point for the media. Thereafter, any conduct thought to reveal character became fair game.

Although many bemoan this new era of intense media coverage of marital infidelity and other eyebrow-raising after-hours conduct, the current rules of engagement are clear. Character is treated as a competence, and every public figure who engages in discrediting activity does so in reckless disregard for the likelihood that the conduct will become a damaging public spectacle.

Thus, even those who are tolerant of infidelity must acknowledge the ethical significance of behavior certain to injure institutions that need public trust as well as a long list of stakeholders including family, friends, supporters, and colleagues.

This is Michael Josephson reminding you that character counts.