The murderous shooting attack in Vienna on November 2 is one more wake-up call for Europeans who think they’ve nothing to worry about from Islamists. But while the battle appears to be one in which the West is waging a struggle against Islamists, an indicator that the extremists aren’t losing is the way anti-Semitism continues to be largely tolerated on the streets of European capitals.

Like the recent horrifying murders in France, the Vienna attack—carried out by a Muslim extremist who had previously been arrested and then released after attempting to go to Syria to join the ISIS terror movement—in the vicinity of a synagogue poses troubling questions about the future of the continent.

Judging by the reported reaction of Austrian authorities, they, like many other officials in Europe, would rather not think about those questions. Instead, they appear to be insisting on believing that attacks such as this one are the exceptions that prove the rule, in which immigrants from North Africa and elsewhere in the Muslim world are finding homes, prosperity and happiness in prosperous Western and Central European nations without forcing those countries to weigh the cost of accepting outsiders to their security or their national identity.

That wasn’t the case in France, where President Emmanuel Macron has responded forcefully to the two terror attacks that appeared to be responses to the start of the trial of the main suspect in the Charlie Hebdo attacks in 2015. That was a seminal event when Islamists murdered 12 people after that satirical magazine published cartoons of the Prophet Muhammad. That same day, another attack also took place at the Hypercacher kosher supermarket in Paris, where hostages were taken and four Jews were slain by a colleague of the Charlie Hebdo terrorists.

But the start of the trial led to more murders. In one, a Chechen Islamist beheaded a French high-school teacher after he showed his class the cartoons. That was followed by the October 29 knife attack at a church in Nice, where a Tunisian immigrant on a personal jihad killed three more people.

In response, Macron declared war on what he called Muslim extremists that he labeled as a threat to the secular tradition of the French republic. While trying to differentiate between protecting the rights of Muslims from the extremists, Macron sought to draw a line in the sand where Islamists who were determined to create a separate extremist Muslim society within France had to be opposed and ultimately rooted out.

For this, he has been assailed by some French politicians as being too weak and others for unnecessarily targeting all members of the Muslim community, who currently make up about 5% of the population.

More ominously, some leaders of Muslim countries have responded to this crisis with exactly the sort of comments that are bound to lead to more terror. Iran’s leaders accused Macron of Islamophobia and rationalized the Charlie Hebdo attacks.

Even Egyptian President Abdel Fattah el-Sisi condemned Macron, as well as the terror attacks, saying that Muslims had “a right for their feelings not to be hurt” by the publication of cartoons they find offensive. Unlike Iran, Egypt is a Western ally and is waging its own war on Islamist extremists in the Muslim Brotherhood. El-Sisi’s remarks, though, were a reminder that no leader in a Muslim majority nation can afford to take a stand on behalf of freedom of expression, even in Western countries, while stifling it at home.

This series of events serves to illustrate Europe’s dilemma.

The Charlie Hebdo attack and the reaction to the trial illustrate that a certain percentage of the Muslim population won’t tolerate the sort of free expression that remains integral to functioning democracies. Yet it’s also true that the sort of measures that Macron is contemplating against Muslim associations that encourage religious extremism would be unthinkable in the United States, where constitutional protections for religious expression protect even Islamists as long as their beliefs aren’t translated into violence. Indeed, even a sensible anti-terror precaution such as the effort by the New York Police Department to monitor mosques where extremists preach was ruled illegal by the courts.

The kind of separatism that Macron rightly fears in France has not happened in the United States. In this case, American exceptionalism appears to have continued to hold true since the overwhelming majority of Muslim Americans want nothing to do with those who justify terror, even if some of those who claim to represent them, such as the Council on American Islamic Relations (CAIR)—founded as a front for supporters of Hamas terrorists, yet masquerades as a civil-rights group—would indicate otherwise.

Europe, however, faces a very different situation, and the predicament of European Jewry illustrates the problem. The rights of American Muslims, like that of any other ethnic or religious minority group, are not in question the way they are in France. But by the same token, neither are Jews at risk when walking down the streets of major U.S. cities as they are in every Western European capital for those who wear kippahs or other identifiable articles, let alone clothing that indicates their Jewish identity.

By tolerating the kind of anti-Semitism that is largely driven by Muslim extremism in Europe, Jews have become—and not for the first time in history—the canary in the coal mine, which is an early indicator of peril for everyone.

Macron’s strong response to terror, like the French Republic’s vigorous reaction to the Charlie Hebdo and Hypercacher murders, is encouraging. Still, as long as Jews feel insecure, the notion that Western freedom will survive and ultimately triumph over the Islamists should not be taken as a given.

That insecurity is measured by the fact that the Jewish population in Europe is in serious decline. As a study recently published by the London-based Institute for Jewish Policy Research indicated, the European Jewish population is the lowest it has been in 1,000 years. The reason for this is obvious. In addition to European Jews having a low birth rate like their Christian neighbors, they are recognizing they don’t have a future even in countries where communities were reconstituted in the aftermath of the Holocaust.

There are serious doubts as to whether Western Europe will fight to defend its liberal values as vigorously as Macron is trying to do. Until Jews feel secure, any optimism that those who agree with Macron will prevail over threats from the Middle East is more of a hope than a realistic prediction.

Jonathan S. Tobin is editor in chief of JNS—Jewish News Syndicate. Follow him on Twitter at: @jonathans_tobin.