People demonstrating in New York City against conservative presidential candidate Donald Trump's recent remarks concerning Muslims. (Photo: Spencer Platt/Getty Images)

The last four weeks have yielded perhaps the most intense debate on religious violence in America since 9/11. The terrorists attacks that claimed 130 lives in Paris on November 13 left presidential candidates debating how open our border should be to Syrian refugees (while allowing for international assistance to the Christian ones). A mere weeks later, a gunman opened fire at a Colorado Planned Parenthood clinic, killing three. In court this week, the alleged shooter declared his guilt, and his warped intentions: "There's no trial," Robert L. Dear Jr. said. "I'm a warrior for the babies." We'll never even get that sort of explanation from Syed Rizwan Farook and Tashfeen Malik, the radicalized husband and wife behind the mass shooting at a San Bernardino social services center that left 14 dead—a tragedy that led GOP frontrunner Donald Trump to call this week for a ban on all Muslims from entering the country.

This has all added up to yield a major spike in Americans' anxiety over terrorism. A new survey published on Thursday by the Public Religion Research Institute shows that 75 percent of Americans believe terrorism is the most important issue facing the country. And respondents didn't mean this in an abstract sense: Almost half say they are worried "that they or someone in their family will be a victim of terrorism."

The closer you look at the Public Religion Research Institute data, the clearer it becomes that the United States has a real double standard when it comes to religiously motivated mass violence. The survey indicated that three-quarters of Americans say that self-proclaimed Christians who commit acts of violence in the name of Christianity "are not really Christian." By contrast, only 50 percent of the public says that self-identified Muslims who commit acts of violence in the name of Islam "are not really Muslim." Journalists and activists have levied this critique at the media for years—that Muslim criminals are automatically "terrorists," while a white, Christian mass shooter is a "lone gunman" or a "lone wolf." This new data shows just how widespread that attitude is. It doesn't help that 53 percent of the American public agrees that Muslims "have not done enough to oppose extremism in their own communities," according to the survey.

You're about five times more likely to be killed by a right-wing extremist than you are by an Islamic radical tinkering away next door.

The fixation on terrorism itself as an existential threat is part of the problem. In contrast to the mass anxiety over terrorism, demonstrably fewer (67 percent) Americans say mass shootings are the most important issue facing the U.S., despite the fact that there have been nearly 353 mass shootings (defined as shooting incidents where at least four people are wounded, a vaguely problematic metric) in 2015 alone. It doesn't really matter that guns have killed far more Americans than terrorism; the Centers for Disease Control and Prevention estimates that 153,144 people were killed by a gun between 2001 and 2013, while the Global Terrorism Database puts the number of people killed in terrorist attacks between 2001 and 2014 at around 3,046. And while lawmakers race to sponsor legislation in the aftermath of a terror scare (like the travel restrictions on foreign visitors proposed this week), changing U.S. gun policy is politically impossible. "In retrospect, Sandy Hook marked the end of the U.S. gun control debate," observed the Telegraph's Dan Hodges, in the wake of June's massacre of black parishioners at a Charleston church by a white supremacist. "Once America decided killing children was bearable, it was over."

This double standard becomes itself more maddening when you consider the breakdown of white nationalist terrorism versus Islamic terrorism. As we observed in the aftermath of the Charleston massacre in June, right-wing extremism kills far more Americans at home than Islamic extremism: The New America Foundation's International Security Program, which tracks deadly attacks since 9/11, indicates that the nine attacks on America by self-styled jihadists since 2001 have only killed about 45 Americans, with the San Bernardino shooting's 14 fatalities registering as the deadliest. By contrast, right-wing extremism has killed 48 people, in twice as many incidents.

Independent research confirms this trend. A separate survey conducted by sociologists in collaboration with the Police Executive Research Forum found that Islam-inspired terror attacks "accounted for 50 fatalities over the past 13 and a half years," while right-wing extremists "averaged 337 attacks per year in the decade after 9/11, causing a total of 254 fatalities." This means you're about five times more likely to be killed by a right-wing extremist—a sovereign citizen, a neo-Nazi, a white supremacist—than you are by an Islamic radical tinkering away next door.

But this isn't all just an annoying example of irrational fears, or an indicator of a rhetorical bias in politicians and newscasters that can be remedied with an army of self-righteous tweets and think pieces. It's absolutely a historical fixture of America's cultural DNA, one that shapes U.S. policy in fundamentally unjust ways.

Consider the political handwringing over refugee policy in the aftermath of the Paris attacks, even though data shows that zero of the 784,000 refugees admitted to the U.S. have been arrested on terrorism-related charges. Despite the promise of religious liberty and economic opportunity, the U.S. has never actually welcomed those "poor, huddled masses" that Emma Lazarus imagined, as Cornell University professor Maria Cristina Garcia argued in a Washington Post op-ed during the height of the post-Paris refugee debate.

Take the 1948 Displaced Persons Act that launched U.S. refugee policy: Passed in the aftermath of the Holocaust, it actually discriminated against Jews and Catholics. Or take President Eisenhower's reluctance to admit Hungarian refugees during their country's rebellion against the Soviets in 1956. Or the American public's opposition to taking in Southeast Asians, who were seeking solace from the dangers of the Vietnam War. We talk about discrimination against Muslim refugees being against our noble American values, but in practice it's as American as apple pie and tax-avoidance.

By contrast, consider the Oath Keepers, who turned up with guns to protect primarily white business owners' properties during unrest in Ferguson, Missouri. Armed white men can operate with impunity because of Americas legacy of vigilantism and rugged individualism—even if they're showing up to intimidate Muslims at a Texas mosque. This nativist xenophobia is a bit ironic considering Protestants and Catholics make up more than half of the U.S. prison population. Or that, despite the gradual decline in hate crimes in the U.S., there were more anti-Muslim incidents in 2014 (154) than Islamic terror fatalities since 9/11. Or that recent research in the Social Psychiatry and Psychiatric Epidemiology indicates that immigrants, despite their social disadvantages, are far less likely to commit crimes or engage in anti-social behavior than native-born citizens.

Prevalence of violent and non-violent antisocial behavior among native-born and immigrants aged 18 and older by immigrant country of origin. (Chart: Social Psychiatry and Psychiatric Epidemiology)

The double standard for religious violence is shocking, but it should really surprise no one. "The main problem nowadays is not the folks with the hoods, but the folks dressed in suits," Duke sociologist Eduardo Bonilla-Silva told CNN in the aftermath of the Ferguson protests in 2014. "The more we assume that the problem of racism is limited to the Klan, the birthers, the Tea Party, or to the Republican Party, the less we understand that racial domination is a collective process and we are all in this game." Islamophobia and the demonization of non-Christian violence didn't begin with Donald Trump. The saddest part of this long, horrible month, though, is that it won't end with him either.