In the novel, Bachmann is a secret agent on his uppers. Well, Philip can relate to that. The character’s been whisked home from Beirut after losing his precious spy network to the clumsiness or worse of the C.I.A. He has been put out to grass in Hamburg, the city that played host to the 9/11 conspirators. Its regional intelligence arm, and many of its citizens, are still living with that embarrassment.

Bachmann’s self-devised mission is to put the score straight: not by way of snatch teams, waterboards and extrajudicial killings, but by the artful penetration of spies, by espousal, by using the enemy’s own weight to bring him down, and the consequent disarming of jihadism from within.

Over a fancy dinner with the filmmakers and the high end of the cast, I don’t remember either Philip or myself talking much about the actual role of Bachmann; just more generally, about such things as the care and maintenance of secret agents and the pastoral role incumbent on their agent runners. Forget blackmail, I said. Forget the macho. Forget sleep deprivation, locking people in boxes, simulated executions and other enhancements. The best agents, snitches, joes, informants or whatever you want to call them, I pontificated, needed patience, understanding and loving care. I like to think he took my homily to heart, but more likely he was wondering whether he could use a bit of that soupy expression I put on when I’m trying to impress.

It’s hard now to write with detachment about Philip’s performance as a desperate middle-aged man going amok, or the way he fashioned the arc of his character’s self-destruction. He was directed, of course. And the director, Anton Corbijn, a cultural polymath in Philip’s class, is many wonderful things: photographer of world renown, pillar of the contemporary music scene and himself the subject of a documentary film. His first feature, “Control” in black and white, is iconic. He is currently making a movie about James Dean. Yet for all that, his creative talents, where I have seen them at work, strike me as inward and sovereign to himself. He would be the last person, I suspect, to describe himself as a theoretical dramatist, or articulate communicator about the inner life of a character. Philip had to have that dialogue with himself, and it must have been a pretty morbid one, filled with questions like: At which point exactly do I lose all sense of moderation? Or, why do I insist on going through with this whole thing when deep down I know it can only end in tragedy? But tragedy lured Bachmann like a wrecker’s lamp, and it lured Philip, too.

There was a problem about accents. We had really good German actors who spoke English with a German accent. Collective wisdom dictated, not necessarily wisely, that Philip should do the same. For the first few minutes of listening to him, I thought, “Crikey.” No German I knew spoke English like this. He did a mouth thing, a kind of pout. He seemed to kiss his lines rather than speak them. Then gradually he did what only the greatest actors can do. He made his voice the only authentic one, the lonely one, the odd one out, the one you depended on amid all the others. And every time it left the stage, like the great man himself, you waited for its return with impatience and mounting unease.

We shall wait a long time for another Philip.