Nationalism is on the rise across the globe. It is key to Donald Trump’s appeal in the U.S. It is the driving force behind resistance to the European Union and its policies in Britain, Italy, Austria, Poland and Hungary. And it is reflected in the success of Narendra Modi in India, Shinzo Abe in Japan and Benjamin Netanyahu in Israel. Even before considering more complicated examples such as Russia, Turkey and China—whose politics have arguably taken a nationalist turn as well—this constitutes a broad revival of nationalist ideals and aspirations.

Many critics see this revival as the greatest political danger of our time. But it is a mistake to think of nationalism as an inherently regressive or destructive political force. In fact, nationalism was the engine that established modern political liberty, and it has been a spur to diversity among nations. It has been embraced by both liberals and conservatives, including revered figures such as Woodrow Wilson and Teddy Roosevelt, David Ben-Gurion and Mahatma Gandhi, Charles de Gaulle and Margaret Thatcher.

What did all of these leaders see in nationalism that made it so attractive? And if nationalism is, in many respects, genuinely attractive, what can be said about the powerful considerations that are cited against it?

Let’s start with the classic arguments against nationalism. In his essay “Notes on Nationalism” (1945), published weeks after the end of World War II, George Orwell provided a critique of nationalism that is still widely invoked today. Calling nationalism a disordered “habit of mind,” he wrote that nationalists identify solely with a “single nation or other unit,” treat it as beyond moral reproach and recognize “no other duty than that of advancing its interests.”

But Orwell goes well beyond nationalism as the term is usually understood. He takes aim at political extremism on behalf of any collective, including churches, economic classes and “such movements and tendencies as Communism, political Catholicism, Zionism, anti-Semitism, Trotskyism and Pacifism.” At the same time, however, Orwell praises patriotism, which he sees as “devotion to a particular place and a particular way of life, which one believes to be the best in the world but has no wish to force on other people.”