This is a great question, because it shows that we live in the age of the media. As soon as the scandal was found out between President Bill Clinton and Monica Lewinsky, the media was all over it. This played two major roles.
First, with the media, all news spreads almost instantaneously. Hence, the rate of speed by which news spreads is completely unparalleled in history. Furthermore, the broadness of the spread of news is equally powerful. People in Asia and Africa were talking about Monica Lewinsky and her blue dress! The point of this is that there is no getting away. This is an important point, because popular opinions matter more than ever. This incident tarnished Bill Clinton for sure.
Second, when we look at things from a historical perspective, we can say that many presidents got away with lots in the past, because of the lack of modern media. From this we can say that mistakes now are amplified to an incredible degree. In short, the media is unforgiving.
In conclusion, all people need to get ready to face the media, if they enter a public career. Hence, one's public persona matters.