We might ask why the 20th century was so barbaric. Surely, there were barbarians during earlier ages. Part of the answer is that during earlier times, there wasn't the kind of concentration of power that emerged during the 20th century. Had Josef Stalin, Mao Zedong and Hitler been around in earlier times, they could not have engineered the slaughter of tens of millions of people. They wouldn't have had the authority. There was considerable dispersion of jealously guarded political power in the forms of heads of provincial governments and principalities and nobility and church leaders whose political power within their spheres was often just as strong as the monarch's.
Professor Rummel explained in the very first sentence of "Death by Government" that "Power kills; absolute Power kills absolutely. ... The more power a government has, the more it can act arbitrarily according to the whims and desires of the elite, and the more it will make war on others and murder its foreign and domestic subjects." That's the long, tragic, ugly story of government: the elite's use of government to dupe and forcibly impose its will on the masses. The masses are always duped by well-intentioned phrases. After all, what German could have been against "A Law to Remedy the Distress of People and Reich"? It's not just Germans who have fallen prey to well-intentioned phrases. After all, who can be against the "Patient Protection and Affordable Care Act"?
We Americans ought to keep the fact in mind that Hitler, Stalin and Mao would have had more success in their reign of terror if they had the kind of control and information about their citizens that agencies such as the NSA, the IRS and the ATF have about us. You might ask, "What are you saying, Williams?" Just put it this way: No German who died before 1930 would have believed the Holocaust possible.