For updates on reaction to the incident described in this article, click here and scroll down.

On May 2, 2017, a polite letter arrived from the Director of the Political Committee of the NATO Parliamentary Assembly (known as NATO PA) asking whether my organization, the Middle East Forum, "might be able to host a set of meetings and discussions" for assembly members.

For those, like me, unfamiliar with NATO PA, it is "a unique specialized forum for members of parliament from across the Atlantic Alliance to discuss and influence decisions on Alliance security." Its Political Committee "focuses on all political questions concerning the security of NATO and its member and partner countries."

The Forum quickly agreed to host the meeting on Sep. 19 on Independence Mall in Philadelphia and began inviting experts to brief the 26 members of parliament from 12 countries, ranging from Norway to Turkey, Poland to Portugal.

Given the centrality of Turkey to both the Syrian conflict and to the deeper issue of NATO's mission (does it fight Islamism as it once did communism?), we invited representatives of two key Turkish factions, both of them Islamist: the government of Recep Tayyip Erdoğan and the movement of Fethullah Gülen. (The two had been closely allied until a few years ago; now the government accuses Gülen of staging an alleged coup d'état in July 2016 and declares Gülen movement members "terrorists," jailing those it can, abominating those it can't.)

Ankara demanded the removal of Çelik from the program. If we refused, NATO PA would cancel out on us.

Emre Çelik, president of the Rumi Forum, a Gülenist intellectual group, immediately agreed to speak. However, for the longest time we could not pry a reply to our invitation out of the Turkish embassy in Washington. Finally, less than a week before the event was to take place, the Political Committee staff informed us that no less than the presidential office in Ankara demanded we remove Mr. Çelik from the program. If we refused, it would cancel out on us.

My initial reaction was, "Fine, cancel it." Having sunk much time, money, and reputation into the conference, however, the Forum hardly relished pulling the plug. We also did not want to join the ranks of Western appeasers, such as NATO PA, who submit to the will of Turkey's dictator, Erdoğan. What to do?

The Turkish delegation loudly interrupted the proceedings when Çelik was invited to the stage, then stormed out.

We adopted an unusual course of action: Yes, Çelik's name came off the program and the embassy diplomat showed up. But with Çelik's concurrence, we arranged for him to enter the meeting through a back door and wait quietly in the wings until I, after speaking in the final session about the disgrace and damage of NATO's submitting to Erdoğan's will, invited him to the podium to address the conference.

As I announced Çelik's presence, the entire Turkish contingent stood up and protested so loudly that our security guards ran up to protect him. The co-chairman of the NATO PA delegation, surprised by my action, which he called a "bombshell," pushed Çelik aside and seized the podium. (For a video, click here.)

On concluding his remarks, the co-chairman attempted to close the meeting but I interfered, asserting it was our event, and again invited Çelik to speak. As he began, first the Turks and then the entire NATO PA delegation exited the hall, leaving behind only our other guests, who proceeded to give him a standing ovation.

I proffer my apology to NATO PA for pulling this trick. But I stand by the deception. It was impossible for us to ignore NATO's founding principle "to safeguard the freedom" of its peoples.

I hope the NATO PA delegates draw inspiration from this small act of defiance.

It was equally impossible to ask the Forum, especially as it met within sight of Independence Hall and the Liberty Bell, to acquiesce to the diktat of a foreign tyrant.

Indeed, despite the walk-out, I hope the NATO Parliamentary Assembly delegates secretly admire our taking a stand against tyranny and draw inspiration from this small act of defiance.

Perhaps they will learn to stand up to Erdoğan's bullying – precisely what they did not do in this instance.

Daniel Pipes (DanielPipes.org, @DanielPipes) is president of the Middle East Forum.