Last week President Trump condemned attacks against American Jews, which is good. So why won’t he condemn attacks against American Muslims? Why is there so little political pressure on him to do so?

Numerically, the problem appears roughly similar. In the ten days following Trump’s victory, the Southern Poverty Law Center chronicled one hundred attacks—or threatened attacks—against American Jews and 49 against American Muslims. In its survey, which encompassed the period between election day and February 9, the progressive news site ThinkProgress counted 70 anti-Jewish incidents and 31 anti-Muslim ones.

The ratio of anti-Jewish to anti-Muslim incidents, in other words, appears slightly over two to one, which mirrors the ratio of Jews to Muslims in the population. According to a 2014 Pew Research Survey, 1.9 percent of Americans are Jewish; 0.9 percent are Muslim . That means that, if the SPLC and Think Progress tallies are correct, Jews and Muslims have a roughly equal chance of being victimized. In fact, Muslims are more likely to suffer an actual assault. Of the 70 anti-Jewish incidents that Think Progress catalogued, only one involved physical attack. (The large majority were bomb threats). Of the 31 anti-Muslim incidents, by contrast, nine did.

But if the scale of the attacks is roughly similar, the political reaction to them has been dramatically different. On February 15 and 16, reporters asked Trump about rising anti-Semitism in two successive press conferences. When Trump flubbed his answers, CNN reported that, “it was fast becoming politically damaging for Trump not to adopt a stern, public line against the [anti-Semitic] incidents.” Even after Trump specifically and forcefully condemned anti-Semitism on February 21, CNN declared that his words “can’t stop questions about his motives.” An NBC News report wondered whether it was “Too Little, Too Late?”

There’s been no similar pressure on Trump to condemn attacks on American Muslims. The press has certainly covered Trump’s attitudes—and those of his top advisors—toward Islam, particularly since he announced a ban on travel from seven majority-Muslim nations on January 27. But attacks on American mosques have received far less attention than the bomb threats against Jewish Community Centers. As far as I’m aware, no reporter has asked Trump about them at a press conference. And no major network would suggest that Trump’s failure “to adopt a stern, public line” against Islamophobia has been “politically damaging.”

What explains the difference? One answer is assimilation. With the exception of African Americans, American Muslims are a largely immigrant community. By contrast, most American Jews came a century ago. That helps explain why Jews are better represented at elite levels of the press and government, and in a better position to press their community’s concerns. Among the people who appear to have nudged Trump into a condemnation of anti-Semitism are his Jewish-convert daughter, who tweeted about the JCC attacks, and his Jewish son-in-law. If Trump had a Muslim son-in-law and a Muslim-convert daughter, they might have pushed him to publicly condemn attacks on mosques. (In fact, they might have challenged his slandering of Muslims throughout the campaign). But the scenario is hard to imagine because the social distance between American Muslims and elite, native-born, families like the Trumps remains so large.

The second answer concerns the way anti-Jewish and anti-Muslim bigotry are discussed in American politics. In Washington, everyone who matters politically considers anti-Semitism an indefensible sin. If a Jewish reporter or activist claims that it is rising, neither mainstream liberals nor mainstream conservatives are likely to accuse her of ulterior motives. Liberals and conservatives may argue about the reasons for rising anti-Semitism. Liberals are more likely to blame the alt-right. Conservatives often link anti-Semitism to criticism of Israel. But neither side minimizes the problem.

Islamophobia, by contrast, evokes a bitter ideological struggle. It’s not that mainstream conservatives approve of vandalizing mosques. But many believe the left is whitewashing Islam. And they view accusations of Islamophobia as an effort to discredit Islam’s critics, e.g. people like them.

Search for “Anti-Semitism” in conservative publications like National Review, The Weekly Standard, The Wall Street Journal editorial page and Commentary and you’ll find analyses of the phenomenon. Search for “Islamophobia,” by contrast, and you’ll find articles with headlines like “Islamophobia is a myth,” “‘Islamophobia’ Is Still Not the Problem,”  “The Islamophobia Myth Hits the FBI” and  “’Islamophobia’ or ‘Truthophobia.’” Often, the term itself is put in quotation marks. Victimization of American Jews is considered a  real problem. Victimization of American Muslims is considered a politically inspired hoax.

These publications aren’t Breitbart. They aren’t blanket apologists for Trump. But even anti-Trump conservatives tend to view “political correctness” as inhibiting an honest conversation about the supposed pathologies of Islam. And they thus ignore accusations of Islamophobia or actively deny them.

This helps explain why Trump faces so little pressure to condemn the spasm of anti-Muslim attacks. His initial failure to forcefully condemn anti-Semitism didn’t only spark criticism from the mainstream media, which Trump delights in belittling. It also sparked criticism from his own ideological side. The Zionist Organization of America, which invited Steve Bannon to its annual gala, insisted that Trump personally condemn anti-Semitism. The Simon Wiesenthal Center, whose founder spoke at Trump’s inaugural, urged him to do more. On CNN, former presidential candidate Rick Santorum, who endorsed Trump, said he was “befuddled” as to why Trump had not spoken out. Even Jake Turx, the Jewish reporter who Trump berated for asking about anti-Semitism, probably only got to ask the question at all because his publication, Ami, is sympathetic to Trump.

No pro-Trump Muslim publications have been invited to presidential briefings. There is no Muslim equivalent of the ZOA or Simon Wiesenthal Center. There’s no former Republican presidential candidate who is as philo-Islamic as Santorum is philo-Semitic. In other words, there’s no influential cadre of people who support Trump, and have earned his trust, yet care enough about attacks on Muslims to challenge his silence on the subject.

Trump was forced to condemn anti-Semitism because in 2017 appearing indifferent to the safety of American Jews is politically dangerous in both parties. In today’s GOP, by contrast, appearing indifferent to the safety of American Muslims is easy. It’s showing genuine concern that might entail a political price.