Political correctness about Islam isn’t confined to America. It also exists in Europe. Last week Germany’s Chancellor Angela Merkel thus learned a sad lesson in Ankara: those who seek to distinguish between Islam and Islamism face accusations that they are condemning a whole religion and are thus being “Islamophobic.” On February 3, 2017, Merkel, while meeting with Turkey’s President Recep Tayyip Erdogan, defended the importance of protecting the right of opposition in a democracy and called for joint opposition to the “Islamist terror” of the Islamic State. Erdogan immediately replied that there it was not acceptable to speak of “Islamist terror” because Islam was a religion of peace. He rejected her efforts to distinguish between “Islamic” and “Islamist” and presented himself as a defender of Muslims in general against the unbelievers.

Unfortunately for her, Merkel’s lesson came in a very public setting, but the message is one that a group of scholars and intellectuals on both sides of the Atlantic and some in the Middle East have been hearing since the attacks of 9/11 as they have tried to make the same point. In numerous essays and books, I and others have argued that an ideology alternatively called Islamism or radical Islam has been the inspiration for a war of terror launched against the West in Europe, the United States and Israel, and against Muslims especially in Iraq, Iran, Afghanistan, Syria, Yemen, Gaza and Lebanon. This ideology, which has Sunni and Shia variations, emerged in the Arab world 1930s and 1940s in the era of fascism in Italy and more importantly Nazism in Germany. Despite sectarian differences that have even led to violence between Islamist groups, the bottom line is clear: Islamism everywhere opposes liberal democracy, denies the state of Israel the right to exist, is blatantly and proudly anti-Semitic against both the religion of Judaism and Jews as a group as well as the state of Israel, and equally proudly calls for terrorist attacks on the people, values and institutions of Western liberal modernity.

The scholarship on this urgent topic includes Paul Berman’s Terror and Liberalism (2004) and The Flight of the Intellectuals (2011), Matthias Küntzel’s Jihad and Jew-Hatred: Islamism and the Roots of 9/11 (2002; English, 2013), Bassam Tibi’s Islamism and Islam (2012), and my own Nazi Propaganda for the Arab World (2009). All draw a sharp line between the religion of Islam and the large majority of its Muslim adherents, on the one hand, and the minority that adopted Islamism as its creed, on the other. We all urged governments on both sides of the Atlantic to make this distinction. Alas, with the exception of France, and that not until after the terrorist attacks of 2015, none did.

Instead, President Bush spoke vaguely of a “war on terror” while President Obama referred to an unspecified “violent extremism.” Such obfuscatory language clouded what was really at stake. In the past sixteen years, it has been patently clear to serious scholars and observers that Islamism was indeed an interpretation, however distorted, of the religion of Islam, that it referred, in however absurd a manner, to existing passages in the Koran and commentaries about it. To say, as President Obama once did, that the Islamic State had nothing to do with Islam took this refusal to make distinctions to an absurd conclusion.

No matter how careful we were, no matter how sound our scholarship, or how reliable our reading of key texts, the advocates of euphemism and avoidance, especially in the past eight years, have refused to state the obvious or to challenge those who claimed that making any connection between terrorism and any interpretation of the religion of Islam was “Islamophobic” and thus an insult to all Muslims. Our government officials failed to mention the well-documented collaboration of Haj Amin al-Husseini, the founder of the Palestinian national movement, with the Nazi regime during World War II and the Holocaust. They did not mention his 1937 essay “Islam and the Jews,” a text that became a canonical interpretation presenting the religion of Islam as being inherently at war with both Judaism and the Jews. They refused to recall that Hassan al-Banna, the founder of the Muslim Brotherhood in Egypt and then the leading Islamist organization in the Arab world, hailed Husseini as a hero when he returned to the Middle East in 1946. The advocates of euphemism and denial refused to discuss publicly the enormous impact of Sayyid Qutb’s viciously anti-Semitic texts, such as his 1952 essay “Our Struggle with the Jews.” The attackers of 9/11 and Osama bin Laden repeatedly and proudly announced their hatred of Jews, Israel and the United States, yet in his eight years in office, President Obama made no effort to educate the American people and the global public about the Islamist interpretation of Islam. The anti-Semitism of the Iranian government received inadequate discussion in Washington as well. Millions of people around the world could see that the terrorists evoked Islamist ideas to justify their barbarism. They could also observe that by far the greatest number of their victims were their fellow Muslims. Yet the era of euphemism and avoidance continued unabated.

It defies logic and credibility that former President Obama and his staff in the White House and State Department were unaware of the scholarship on Islamism. In 2011, for example, Tibi’s very important Islamism and Islam was published by Yale University Press, but it received scant attention in the general-interest reviews, in public discussion, or within the Obama administration. Yet whether Obama knew better or whether he was so much a product of the politically correct academy that he actually thought that the Islamic State had nothing to do with Islam was irrelevant. For whatever reason, during his entire term in office, he and his officials continued to voice euphemisms about an unspecified “organized extremism” that echoed the equally uninformative term “war on terror” of the Bush years. The great disappointment of Obama in this regard is that this highly intelligent and nuanced thinker declined to place his best talents in the service of enlightening the public about the distinction between this very influential and consequential interpretation of Islam and the more widespread interpretations of Islam that were not fueling terrorism.

One result of the refusal to speak frankly about Islamism and terror since 9/11 is Donald Trump’s horrible executive order banning immigration from seven majority-Muslim countries. This widely deplored policy replaces the euphemisms of the Bush and Obama years with a general suspicion of Islam. We have moved from denial of realities in the era of political correctness to denial of distinctions in a new era of prejudice and ignorance. While the Obama era refused to acknowledge facts evident to millions, the beginnings of the Trump administration, now in a tone of intense anti-intellectualism and suspicion, defy both common sense and well-known facts. In a country such as ours, blessed as it is with a highly educated and sophisticated political and intellectual establishment, the continuing denial of distinctions has been and remains not just an intellectual embarrassment but a dangerous misunderstanding that fosters disastrous policy blunders.

As Tibi, Berman, Küntzel and I wrote our works on Islamism, we faced the expected criticisms of Islamophobia from scholars of Middle East studies, as well as political activists who refused to pay attention to the evidence in widely available Islamist texts. Yet we also faced criticism from those on an emerging hard right who argued that there was in fact no distinction between Islamism and Islam, that the problem was the religion of Islam itself—and that in seeking to draw attention to diverse interpretations of Islam and make fine distinctions, we had become naïve apologists for a dangerous religion. In recent years, Stephen Bannon and Breitbart.com gave those voices a platform. Michael Flynn, now Trump’s national security adviser, has written about the threat of radical Islam but he too shows no inclination to distinguish it from Islam in general. Now their simplified view of Islam is guiding American foreign policy and has handed the Islamists an enormous propaganda victory. From liberals and leftists of the Obama years who refused to speak the truth about Islamism, we now have populists and nationalists like Trump who also refuse to make any distinctions in public. Where Obama declared an interpretation of Islam off-limits in discussion of the sources of terrorism, Trump now defames an entire religion, offending hundreds of millions of people and doing vast damage to the good name and national interests of the United States.

It is tempting to suggest that the transition from Obama to Trump is one from complexity to simplicity. In important ways that is surely the case. Yet we must also recognize a continuity. It is a failure of leadership and courage not to tell the American people and people around the world that it is possible for democratic leaders to make distinctions, and not to explain that we can do far better than perpetuate the blanket generalizations that have now dominated the public rhetoric of three American presidents.

It has become clear that Trump and the people advising him view the religion of Islam per se as the problem. To their way of thinking, people such as myself and others mentioned above are naïve because we focus on interpretations of a religion rather than assuming it must mean one and only one thing. Because, like their predecessors in the Oval Office, but for very different reasons, they refuse to distinguish Islamism from Islam, they are causing joy among the jihadists who seek to turn all believers in Islam against the West.

In January, Pascal Bruckner published Un racisme imaginaire: islamophobie et culpabilité (An imaginary racism: Islamophobia and guilt). We would do well to listen to voices such as Bruckner’s and that of France’s brave Prime Minister Manuel Valls, who had the intelligence and courage to speak the truth after the attacks on Charlie Hebdo, the Bataclan and the Hypercacher supermarket: Valls said that France was not at war with Islam or with Muslims but with radical Islam. Now that Angela Merkel, whose decisions have saved thousands of Muslims from Islamist terror, has publicly made the same point, Americans should learn from these speakers of the truth in Europe.

­­­Effective opposition to Trump will require some soul-searching among those who have refrained from speaking frankly about Islamism since 9/11. In the warp-speed world of Twitter and social media, everyone interested in this issue would benefit from taking time to read the scholarship that the two previous administrations and too much of the foreign-policy establishment dismissed or ignored. In the past, democratic leaders have educated citizens about complicated issues, and they can and should do so again.

Jeffrey Herf, who has written numerous books on Nazi and modern Germany, is Distinguished University Professor of modern European history at the University of Maryland in College Park. In May 2016, Cambridge University Press published his Undeclared Wars with Israel: East Germany and the West German Far Left, 1967–1989.