From a post by AVI:
I'll tell you something about lying from having to deal with it so much all day (not just my patients, but their agencies and families as well). When someone refuses to take any responsibility, blaming everything on someone else, they are usually lying. If they thought they were only 10 or 20% at fault they would pony up, lay out the facts, and trust that most observers would get it right. If they are 50-70% at fault they would admit to some responsibility and try to spin the impression on the rest. Only when people are well over 70% at fault do they have to take a reverse strategy and avoid the facts and try to construct a simple narrative of blame that they hope catches on with people. When people make categorical statements of blame, it's like Honest John's Used Cars.
A word of caution. Some politicians have perfected statements of appearing to take responsibility in their introductory comments but quickly moving on to zero blame for them.