In the wake of the terrorist attacks in Paris and San Bernardino, Islamophobia has become a powerful and divisive issue in American politics. The two main political parties are increasingly defining themselves by sharply different rhetoric and policies on the treatment of Muslims, both in the United States and internationally. These issues dominated the Republican debate, and are likely to be equally important when the Democratic candidates take the stage on Saturday.

How did Islamophobia become a litmus test dividing the two parties? The answer long precedes the candidacy of Donald Trump.

As recently as the presidency of George W. Bush, Republican elites successfully clamped down on Islamophobia. As Duke University sociologist Christopher Bail points out in his book Terrified: How Anti-Muslim Fringe Organizations Became Mainstream, the 9/11 attacks led to the American public as a whole becoming more positively disposed to Islam. In a poll conducted in 2000, 45 percent of Americans has a favorable view of Islam. This figure rose to 59 percent by November of 2001, in the immediate aftermath of 9/11. This shift in public attitude occurred because President Bush and the elites in his party were vocal in insisting that America was at war not with Islam, but with a jihadi fringe.

The bipartisan consensus against Islamophobia that existed in 2001 has collapsed in the current election. Donald Trump has polarized the Republican Party with his call for an indefinite moratorium on Muslims being admitted into the United States. Although this specific policy has been condemned by most of his rivals, they’ve all echoed Trump’s clash of civilization rhetoric in one form or another, ranging from limiting Muslim refugees into the United States to monitoring (and possibly closing down) mosques. Senator Marco Rubio is considered more moderate than Trump, but he made an analogy between Muslims and Nazis. Speaking with George Stephanopoulos on ABC’s This Morning last month, Rubio argued that refusing to say that radical Islam is a threat is “like saying we weren’t at war with Nazis ’cause we were afraid to offend some Germans who may have been members of the Nazi party, but weren’t violent themselves.” By Rubio’s analogy, jihadis are the most violent Nazis while ordinary Muslims are run-of-the-mill Nazi party members. 

Hillary Clinton and the other Democrats have been quick to seize upon such remarks as a way of distinguishing the two parties. In a “message to Muslims,” Clinton pointedly called out not just Trump but the Republican party at large. “Now some Republican candidates are saying that Donald Trump’s latest comments have gone too far,” Clinton noted. “But the truth is, many GOP candidates have also said extreme things about Muslims.” Both Bernie Sanders and Martin O’Malley have made similar comments.

More broadly, the views of the candidates reflect a sharp partisan divide in the electorate. According to polling in November, 57 percent of Democrats support a plan to accept 10,00 Syrian refugees, as against 15 percent of Republicans. 

What happened to the bipartisan consensus against Islamophobia? As Bail details in Terrified, the rise of modern, virulent Islamophobia in America started off as a civil war within the Republican Party. While Bush took a stance against Islamophobia, a fringe group within his party, led by figures like Frank Gaffney Jr. of the Center for Security Policy, wanted a larger war against Islam, seeing the jihadis as not a minority within the faith but representative of the religion with a large percentage of Muslims on their side. Gaffney was even willing to argue that leading Republicans like Grover Norquist were either weak on terrorism or covertly aligned with radical Islam.

While Gaffney and his fellow Islamophobes were fringe figures, they received an inordinate amount of press attention, in part because the media loved the inherent drama of their authentic outrage. But Gaffney in particular was attractive to some liberals, including the New Republic on one occasion, because he provided a stick with which to attack the Bush administration. 

While fringe Islamophobes basked in media attention, moderate Muslim groups that condemned terrorism and called for a political analysis of the roots of the problem were largely ignored by the press. As Bail notes, the “complex, dispassionate statements [of mainstream Muslim American groups] were easily overshadowed by the pithy emotional auguries of anti-Muslim organizations that warned of a looming clash of civilizations between Islam and the West.” Further, as mainstream Muslim American groups started to condemn figures like Gaffney, that only served to raise the visibility of fringe ideas. Muslim American organizations were caught in a trap where if they didn’t answer the Islamophobes they would be letting libels go unchallenged but debating the Islamophobes helped spread the very ideas being challenged.

With the rise and election of Barack Obama, whatever trepidation Republicans elites might have had about Islamophobia disappeared. In the new political circumstances, they were no longer defending a Republican president from fringe figures like Frank Gaffney, but rather seeking to attack a Democratic president with the middle name Hussein using Gaffney-created memes.

As Rosie Gray reported in Buzzfeed earlier this week, “On Monday, four Republican presidential candidates appeared either via video or in person at an event for Gaffney’s group, the Center for Security Policy, ahead of Tuesday’s Republican primary debate here in Las Vegas.” The four candidates were Rick Santorum, Carly Fiorina, Ben Carson, and Senator Ted Cruz. Now seen as a front-runner along with Trump and Rubio, Cruz was particularly effusive in praising Gaffney. “Frank is a patriot, he loves this country and he’s clear eyed about radical Islamic terrorism,” Cruz said.

As Cruz’s words make clear, fringe Islamophobia is now mainstream Republican thought. One big challenge for Democrats in the coming debate and next year’s election is to come up with vigorous language to fight this now virulent Islamophobia. But given the history of Republican Islamophobia, it’s worth asking how effective even the strongest language from the Democrats could be. Perhaps the only way to stem the tide of Islamophobia is for powerful GOP figures like George W. Bush stand up against it. But there is scant evidence that such Republicans are willing to do so.