Imagine a seminar in Washington. Around the table are Bernie Sanders supporters and alt right activists, fans of Hillary Clinton and Donald Trump voters, auto workers and Wall Street bankers, abortion activists and Evangelical Christians. And all discussing the question of America’s political future, civilly and articulately, with deep disagreements but also with mutual respect.

It would be difficult to imagine this in Washington. Still less that a similar seminar could take place in Istanbul. Yet, when I gave a lecture there last month, that was just what it felt like. I was talking about populism and immigration – both issues of deep interest and divided opinion in Turkey. Around the table were students of all political persuasions – supporters of the ruling AKP party and critics, liberals and social democrats, Turkish nationalists, Kurds and Armenians. All deeply engaged in a contentious debate, but all with a commitment to open dialogue.

The seminar was organized by the European School of Politics, a brainchild of Osman Kavala. Kavala is one of the most important intellectual and cultural figures in Turkey. Last week he was arrested. Detained now for over a week, charges have yet to be laid. There have, however, been a flood of insinuations in the press – that he is an enemy of Turkey, that he has links with terror groups and that he was involved in last years failed coup. The insinuations are nonsense. They are also ominous.

Osman Kavala has played a prominent role both in defending the rights and liberties of all in Turkey, including Kurds and Armenians, and in bringing together people of different political viewpoints to discuss their differences in civil debate.  He has funded a swathe of projects seeking to nurture trust between Turkey and Armenia. He is chair of Anadolu Kültür, an organization promoting cultural pluralism in Turkey, aiming ‘to build bridges between different ethnic, religious and regional groups by sharing culture and art’. He has worked tirelessly to help restore ancient cultural treasures, including Armenian and Greek churches, that have often been left to decay across Anatolia. He was an instrumental force in establishing İletişim, a publishing house that strives to promote young Turkish authors of all backgrounds.

Osman Kavala has played an important role not just in encouraging discussion inside Turkey but also in presenting the complexities of Turkey to the outside world. His work has been invaluable in making many people outside the country understand and appreciate Turkey, undermining many prejudices. But it has also inevitably created hostility within certain circles in which the nurturing of such open dialogue and debate is seen as a threat.

His arrest and detention comes just as 11 human-rights defenders, including Amnesty’s director in Turkey Idil Eser, German national Peter Steudtner and Swedish national Ali Gharavi, have gone on trial in Istanbul, on charges of supporting terrorist groups.  There is a separate trial of  Amnesty Turkey’s chair, Taner Kilic, who is also facing charges of terrorism and involvement in last year’s failed coup attempt.

Erdal Dogan, a prominent human rights lawyer who represents Idil Eser, has talked of such arrests as part of ‘a push to silence all of the government’s existing and potential critics.’ More than 60,000 people have been arrested and more than 110,000 fired from public service since the July 15 coup attempt. ‘It kicked off with journalists and elected politicians’, observes Dogan. ‘It is continuing with a second wave of arrests of civil society activists. The final phase against professional chambers, lawyers, doctors, environmentalists, is yet to come.’

Many people, in Turkey and outside, are working for Osman Kavala’s release, and that of thousands of others arrested and imprisoned in similar circumstances. In a world of fragmented societies, and of lives lived in echo chambers, Kavala is an indispensible figure. Let us hope he is able to continue his work before long.