Come on, Jeremy Corbyn, give us the full Jack Nicholson. We can handle it

I wonder if Jeremy Corbyn has seen A Few Good Men? The cultural life of most politicians is fairly mysterious, with many saying they don’t have time for one. Boris Johnson occasionally claims his top movie is Dodgeball. I once asked Nigel Farage what his favourite film was, and he floundered so long that I eventually started chucking out suggestions like life-rings. Nigel was sufficiently desperate to be saved that he grabbed hold of Love, Actually. Yes, he said gratefully, Richard Curtis movies were his favourite movies. “English stuff, you know.”

Mmm. I do know. But I don’t know as much as I’d like about Corbyn’s cinematic downtime. I do know that on a cold winter evening, Jeremy and I would probably have different answers to the question: “Do you want to keep everyone at a draughty planning meeting till midnight, or do you want to get a takeaway and watch Vin Diesel be out-acted by a car again?” That is merely one of the 983 reasons Corbyn is a politician and I’m not. He’s always been on the right side of the Fast and Furious franchise.

But I mention A Few Good Men (screenplay by Aaron Sorkin) because of Jack Nicholson’s famous cathartic speech in that courtroom drama. Nicholson plays the commanding officer of what was, back when the film was released, a little-discussed US military base by the name of Guantánamo Bay. Military lawyer and desk johnnie Tom Cruise is attempting to get to the bottom of his exact role in the fatal “code red” hazing of a weak soldier. Trailer line: present, but not involved.

I’m kidding, of course. But the colonel is a charismatic figure, who doesn’t think he’s done anything wrong, much less that he should be asked to justify his actions – taken in a higher cause, beyond his critics’ understanding – by anyone. And certainly not by a whiny brat like Cruise, who he regards as on the wrong side of everything. Yet on Cruise goes. Did you do this, did you do that, I’m entitled to know this, I’m entitled to know that ... When he declares he wants the truth, Nicholson famously explodes: “You can’t handle the truth!”

Still, he’s going to give it to him. The subsequent speech is a study in the complexities and compromises of a perverse morality, as the soldier outlines the trade-offs of “a life spent defending something”. “You have the luxury of not knowing what I do ... My existence, while grotesque and incomprehensible to you, saves lives.” But Cruise keeps asking him if he ordered the code red, and in the end, Nicholson owns it: “You’re goddamned right I did!”

Well. The dam breaks and it’s quite a relief. I don’t know what the Labour news grid says is happening next week. But as far as the emotion graph of this summer goes, surely it’s now time for Corbyn’s “You can’t handle the truth” speech? If this were the movies, Corbyn would be finally moved to declaim his personal philosophy, in a way that – like it or lump it – explained the lot. And if anyone dared to ask one more question after it, I’d imagine the answer would be: “You’re goddamned right I honoured the Black September!”

So where is it? On the downside, Corbyn hasn’t got Sorkin to write it for him. But for me, Gary Younge writing you one is just as aspirational – and my Guardian colleague did just that, in yesterday’s paper. I may not agree with parts of it – but it’s not my speech. Unfortunately, it doesn’t seem to be Corbyn’s either. His failure to own his past without vacillation or press office misdirection is a weakness. Unlike Nicholson’s colonel, he’s not accused of any crime.

So the question becomes: why isn’t he making it? Who is deemed unable to handle the truth? Not his supporters, who can certainly handle the truth (and in some cases, quite a lot of untruth, too). And the media being unable to handle his version of the truth seems to play well for Corbyn. Surely it can’t be that he has decided it is expedient not to embrace the judgments of a life always marketed as the good kind of realpolitik?

I suppose there’s a chance that the person having difficulty handling the truth is Corbyn himself. He never expected to be Labour leader, and under this level of scrutiny. Perhaps he is only now beginning to examine some of the things at which he was present – but not involved – in the years when no one was looking. There is, let’s face it, quite a lot to examine. Corbyn’s sheer volume of historic fringe activity reminds me of a scene featuring Steve Coogan’s character Paul Calf (itself now more than a quarter of a century old. Eek). Anyway, Paul has a vague sense he might know the chap he’s talking to. “You threatened to hit me,” comes the reply, “about a year ago?” Paul looks blank: “So many faces, you know … ” There is something of this to Corbyn’s decades of adventures in freelance peacemaking. So many wreaths, you know …

Of course, the sense that you’ve done so much of something questionable you almost can’t remember what you’ve done is not unique. Occasionally, I get about halfway through something like Universal Soldier II before it dawns on me that I’ve actually watched this rubbish in the 1990s but forgotten about it. And so with Corbyn, who gives the impression of struggling to place things in his past, and even then being on the back foot about them. He’s done quite a lot of this rubbish. Not all of it has been rubbish – not even remotely. But some of it has. And some of it has been absolute trash. That, perhaps, is the hardest truth to handle – but until he does, we’re stuck with this drama on loop.

• Marina Hyde is a Guardian columnist