During the first week of 2016, Supreme Court Justice Antonin Scalia gave what he called a “sermon” in which he said the U.S. Constitution can favor religion over “non-religion.” He was right and, moreover, that is as it should be.

Why should the Constitution favor religious belief over unbelief -- atheism? History provides an answer. Many atheists are fond of reminding people that when it comes to crimes against humanity, Christianity has much to answer for including the Thirty Years War, the Inquisition, and involvement with slavery. But two out of three of the worst mass murderers in all of history were atheists and the third might best be described as pagan.

According to Rummel’s Death by Government, Stalin’s Union of Soviet Socialist Republics – an atheist state -- murdered about 62 million of its own people during its 75 years of existence. Between 1948 and 1976, another explicitly atheist state, Mao’s People’s Republic of China murdered 35 million of its own people primarily through deliberate starvation. The third worst mass murderer, Hitler’s Nazi Germany, killed 21 million persons.

This is not to say that every atheist is a potential mass murderer. There are ethical self-proclaimed atheists and unethical self-proclaimed Christians. But to paraphrase author and journalist Damon Runyon, mass murderers may not always be atheists, but that's the way to bet.

Why might atheists value other people’s lives less?

The U.S. Declaration of Independence states: “We hold these truths to be self-evident, that all men are created equal and endowed by their creator with certain unalienable rights including life, liberty, and the pursuit of happiness.”

These truths are self-evident to Christians and Jews who believe that everyone is endowed with an immortal soul; that everyone deserves to be treated as an end -- not as a means. But the basic equality of man is not self-evident to an atheist who depends only on personal observation or scientific enquiry to discover truth. Personal observation and science tell us that people are not equal in many ways; some persons are stronger, smarter, more self-sacrificing, kinder, more considerate, etc. then others.

It seems a small step from the scientific observation that people differ in key aspects to the conclusion that some people, who we think are ignorant, malicious, or self-centered, should not be trusted with positions of leadership, influence, or even the right to vote. Based on personal observation, might one conclude that some people have value and others do not? Is it possible for an atheist to construct a morality based on the fundamental worth of the individual? And is such a morality sufficient to prevent mass murder?  

Men and women often know what the right thing to do is, but do the wrong thing instead. We treat our fellow humans as means to our own happiness rather than as ends in themselves. It is insufficient to simply know what is right -- most of us must be motivated to do what is right.

There are at least three motivations for a person to avoid doing something that he or she knows is wrong. First, you might avoid doing anything that would get you into trouble with the law -- the police factor. Second, you might avoid doing anything that would leave you feeling ashamed if someone whose opinion you respect found out -- the mom factor. Finally, you avoid doing anything that violates your religionist beliefs of right and wrong -- the God factor. An atheist might be expected to have the same reaction to the police or mom factors. But if he was in a situation where the police and mom would not discover his crime or would not object if they did, would not an atheist find it easier to do what he rationally thought was best for himself regardless of the adverse impact on another?

The Soviet Union’s Stalin and China’s Mao didn’t murder tens of millions by themselves; they required hundreds of thousands or millions of ordinary people to assist in committing their horrible crimes. And if most of the population were atheists then this facilitated recruiting participants in their mass murders. If the police and people you respect are encouraging you to kill the villain of the hour -- whether he is called kulak, revisionist, or is a member of some racial or ethnic group -- why would an atheist hesitate? Especially if a refusal to participate in a crime would endanger his family or himself?

Therefore, atheists face two hurdles to treating their fellow humans as possessing inherent value. First, the equality of worth of all persons and their possession of unalienable rights, which are fundamental articles of faith among Jews and Christians, are extremely difficult to prove scientifically. Second, atheists, by definition, are missing the belief that there are crimes that will endanger their immortal souls. If they can overcome the factors of police and mom, atheists are more likely to pursue their narrow self-interest regardless of the adverse impact on the life, liberty, or happiness of others.

Therefore, Justice Scalia was correct. Although the United States should never favor one religion over another, if we cherish liberty and justice then it is important that our laws and society favor religious belief over atheism.

Frank R. Gunter, Ph.D. is a professor of economics at Lehigh University, a senior fellow of the Foreign Policy Research Institute and a retired Marine colonel.