"My colleagues and I did a study about 10 years ago looking at the two different parties in the United States"not in terms of ideology or policies but purely in terms of violent death rates"and, astonishingly, we found that over a 110-year period, almost without exception, whenever there was a Republican president who was elected, the murder and suicide rates would double, and whenever there was a Democratic president elected, the murder and suicide rates would halve."