Leaders-Can they change their moral compass?

I recently read a comment out on the LinkedIn group, Center for Creative Leadership, titled LEADING LIKE A KENNEDY. I made a comment that I wouldn't want to lead like Ted Kennedy based on his moral compass being very skewed; an example being Chappaquiddick.

The discussion around my comment got very lively with one side disagreeing and believing that leaders can change when the pain is great enough.

So my question now is, can leaders change and make a 180 degree reversal? I know small changes can take place in behaviors but do their morals and ethics change or do they just get smarter at hiding their true identity?