In his magisterial work on the twentieth century, Modern Times, historian Paul Johnson highlights how in the 1920s Germany transformed from being “exceptionally law-abiding into an exceptionally violent society.” A key factor, according to Johnson, was an erosion of the rule of law and partisan acceptance of political violence against groups disdained by the State. Johnson notes that from 1912-1922, there were 354 murders by the Right (proto-Nazis) and 22 by the Left (Marxists).

Those responsible for the every one of the left-wing murders were brought to court; ten were executed and twenty-eight others received sentences averaging fifteen years. Of the right-wing murders, 326 were never solved; fifty killers confessed, but of these more than half were acquitted despite confessions and twenty-four received sentences averaging four months.

The conditions that lead to the rise of Nazism in Germany plex and varied. But this tolerance by the state of several hundred murders certainly aided in the creation of a state that would, within a decade, sponsor the murder of several millions. As history has repeatedly revealed to us, government hostility to specific groups is highly correlated with social hostility to those same groups.

That lesson is reinforced by the latest Pew Study on the “Rising Tide of Restrictions on Liberty.” As their research shows, “higher scores on the Government Restrictions Index are associated with higher scores on the Social Hostilities Index and vice versa. This means that, in general, it is rare for countries that score high on one index to be low on the other.”

As the study points out, “Restrictions on religion rose not only in countries that began the year with high or very high restrictions or hostilities, such as Indonesia and Nigeria, but also in many countries that began with low or moderate restrictions or hostilities, such as Switzerland and the United States.”

The rising tide of restrictions in the latest year studied is attributable to a variety of factors, including increases in crimes, malicious acts and violence motivated by religious hatred or bias, as well as increased government interference with worship or other religious practices. For instance, a November 2009 constitutional referendum in Switzerland banned the construction of minarets on mosques in the country. In Indonesia, more than two dozen churches were forced to close due to pressure from Islamist extremists or, in some instances, local officials. And in Nigeria, violence between Christian and munities, including a series of deadly attacks, escalated throughout the period.

Despite the claims of Western nations to support religious freedom, restrictions on religion have continued to rise in each of the five regions of the world—including the United States.

The share of countries with high or very high restrictions on religious beliefs and practices rose from 31% in the year ending in mid-2009 to 37% in the year ending in mid-2010. Because some of the most restrictive countries are very populous, three-quarters of the world’s approximately 7 billion people live in countries with high government restrictions on religion or high social hostilities involving religion, up from 70% a year earlier.

Take a moment to consider the implications of that statement: Almost four in ten nations in the world have very high restrictions on religious beliefs and practices and three out of every four people on the planet live in countries where both government and society is hostile to some religious believers.

As history has shown time and time again, where there is hostility toward religious groups there will be instability, violence, and warfare. This is why the moral center and chief objective of American diplomacy should be the promotion of religious freedom. As Nathan Hitchen explains,

The logic is that religious freedom is pound liberty, that is, there are other liberties bound within it. Allowing the freedom of religion entails allowing the freedom of speech, the freedom of assembly, and the liberty of conscience. If a regime accepts religious freedom, a multiplier effect naturally develops and pressures the regime toward further reforms. As such, religious liberty limits government (it is a “liberty” after all) by protecting society from the state. Social pluralism can develop because religious minorities are protected. And the prospect of pluralism in the Middle East is especially enticing as it bats the spread of Islamic radicalization.

Of course religious liberty promotion is no more a political science panacea than was democracy promotion. But as Hitchen notes, “Religious liberty would help society grow plex that no totalizing ideology, no philosophical monism, could feasibly dominate the public square, because no single ideology would accurately reflect social reality.” That’s a modest goal, no doubt, but one worthy of being embraced by Americans. A world where everyone can worship freely is a safer world for everyone.