Anxiety and fear were palpable among American Muslims last week after the mass slaughter in two mosques in Christchurch, New Zealand: Would a violent attacker enter their mosque, too? But even in their moment of vulnerability, one lawmaker insisted Muslims were the “real cause of bloodshed.” Fraser Anning, a senator in Australia, said the core problem was Islam.

“The entire religion of Islam is simply the violent ideology of a 6th-century despot masquerading as a religious leader. … The truth is that Islam is not like any other faith. … It is the religious equivalent of fascism,” he said. “And just because the followers of this savage belief were not the killers in this instance does not make them blameless.”

For many Americans, Anning’s statement may seem like an outlier — an extreme right-wing sentiment that does not reflect mainstream politics. But it taps into something strategic and concerted, the idea that “Islam is not a religion.” Islam, this idea suggests, is instead a dangerous political ideology, and therefore Muslims have no right to respect, dignity or First Amendment protection for religious liberty.

The argument has been circulating for some time, but it has gained ground in recent years, at least partly because the voices making the argument have a prominent platform in the Trump administration. Former national security adviser Michael Flynn said “Islam is a political ideology” that “hides behind the notion of it being a religion.” Former White House aide Sebastian Gorka and former White House chief strategist Stephen K. Bannon have also questioned Islam’s status as a religion. Fred Fleitz, who in 2018 was named chief of staff for President Trump’s National Security Council, has said in the past that American Muslims are susceptible to a “radical worldview that wants to destroy modern society, create a global caliphate and impose sharia law on everyone on Earth.”

These claims attempt to legitimize the restriction of Muslims’ rights in the defense of American values. To allow Muslims free religious exercise, in their minds, is to open the door for a Muslim takeover of the United States. In my forthcoming book, “When Islam Is Not a Religion: Inside America’s Fight for Religious Freedom,” I track the impact of this argument in several key areas of religious exercise.

If Islam is considered a dangerous political ideology, not a religion, then Islamic law is dangerous, too, some proponents argue. In January 2006, an attorney named David Yerulshami started a nonprofit dedicated entirely to the cause of fighting Islamic law, which he referred to as “sharia.” On his group’s website, he likened observance of Islamic law to sedition and proposed making observance of the law “a felony punishable by 20 years in prison.” In 2009, with the emergence of the tea party movement, he had the opening he needed to take his effort national — and with the help of a well-known anti-Muslim agitator, Frank Gaffney, he developed a model statute that stops judges from considering any rulings that are based on Islamic law.

The model statute is enacted in various forms in 43 states. In practice, the “anti-sharia” laws restrict the ability of Muslims to use religious arbitration to manage their personal affairs. Arbitration by other religious groups — such as Orthodox Jews and Christian groups like InterVarsity — is common and a fairly uncontroversial form of religious exercise, but the laws single out Muslims for suspicion.

The depiction of Islam as a dangerous ideology, not a religion, has also been used to advocate against religious accommodations for Muslims in the workplace. Pamela Geller has argued that Muslim women seeking to wear a headscarf and Muslim truck drivers who ask to be exempt from delivering alcohol for their employers are trying to “impose Islam on the secular marketplace.”

An even starker example is the 2010 case against the Islamic Center of Murfreesboro, Tenn. Joe Brandon Jr., the attorney representing the residents who opposed the mosque, argued in court that the mosque should receive none of the special protections afforded other houses of worship because, he said, Islam is not a religion. He spent six days of court proceedings peppering witnesses with incendiary questions, such as, “Isn’t it true that in the Koran, Mohammad had a 6-year-old wife that he had sex with? . . . Is that your idea of what a religion is?”

Brandon lost his case, but in the years that followed, his strategy has been replicated in mosque controversies across the country.

Mosque projects became proxies for a battle pitting Islam against the West or against Judeo-Christian culture. Gaffney’s Center for Security Policy even produced a “how-to manual” for mosque opponents, or as the report describes them, “patriotic Americans who are ready to counter the leading edge of Islamic supremacism.” Many of the tactics mosque opponents use — such as nitpicking about parking allotments and plot sizes to delay and ultimately defeat construction plans — are taken straight from the manual.

In recent years, the strategies have been used to oppose Muslim cemeteries, too. For example, in 2016, Muslim communities faced fierce opposition in four U.S. cities. Some residents of Farmersville, Tex., led by Baptist pastor David Meeks, said the proposed cemetery site was actually for a mosque or even possibly a terrorist training center. According to Meeks, Islam is a “quasi-pseudo religion” and “the danger is so real that I must do everything I can to try to stop it.” Other residents sent death threats to the city council and planning members.

Then there is the spate of arsons and bombings that has plagued mosques across America. In August 2017, worshipers in a mosque in Bloomington, Minn., were in the midst of morning prayers when an explosion went off. In 2016, three men in Garden City, Kan., conspired to bomb an apartment complex that served as a mosque for Somali refugees. In 2017, five mosques were burned in the span of 10 weeks. Denying Muslims the right to pray in peace, without fear of violence, or bury their dead in Muslim cemeteries shows how the delegitimization of Islam dehumanizes Muslims.

To some extent, Trump and others in his circle have also reflected this sentiment in their responses to the attack in New Zealand. None of the Trump administration’s condolences so far have used the words “Muslims” and “Islam” — Secretary of State Mike Pompeo offered “personal condolences to the nation of New Zealand”; Homeland Security Secretary Kirstjen Nielsen expressed sympathy for the “victims and their families”; White House press secretary Sarah Sanders also mentioned the “victims and their families.” Trump went as far as pointing to the “horrible massacre in the Mosques.” But neither he nor anyone else in his administration has used the words “Islam” and “Muslims.”

Meanwhile, on Sunday, Trump passionately defended Fox News host Jeanine Pirro, who stated on air that Rep. Ilhan Omar (D-Minn.), because she wears a headscarf, is inherently opposed to the U.S. Constitution. It may just be a coincidence, but many hear the message that Islam is not like other religions.

Asma T. Uddin, a religious liberty lawyer and scholar, is the author of the forthcoming book “When Islam Is Not a Religion.”

Correction: An earlier version of this article misstated Fred Fleitz’s first name.