In the film Manhattan Murder Mystery, Woody Allen is trying to prevent his wife from leaving their apartment in the middle of the night to investigate strange noises next door. "I forbid you to go," he insists. "I'm forbidding!"
Naturally, she ignores him and does it anyway. He's left standing in the doorway, feebly fuming: "Is that what you do when I forbid you? I'm not going to be forbidding you a lot, if you do."
That's basically every Secretary of State for Northern Ireland in recent years. He, sometimes she, stands there, warning Sinn Fein and the DUP of the dire consequences of not coming to an agreement, and the two parties just ignore the poor sap, who's left warning that they might get away with not listening to him on this occasion, but, just you wait, next time will be a different kettle of fish. Except it isn't. It's always exactly the same.
Monday was the latest deadline to whoosh by without a breakthrough. There absolutely had to be a written agreement by the end of the day, no ifs, no buts, or James Brokenshire was going to step in and exert his authority.
Monday came. Tick, tock. No agreement. Imagine that. The minister was left with no choice but to pull the plug on the whole charade, right? Wrong.
Instead, like an inexperienced supply teacher facing a class of uncooperative pupils, Brokenshire was reduced to sending out a Press release insisting the parties had "made further progress" and so should be given more time.
Deadlines have ceased to have any meaning whatsoever. At this stage, they're like promises from a lecherous rock star to his doting wife to be faithful on tour. The last 10 months have seen a bumper crop of such ultimatums that never really were.
The passing of the first one earlier this year was solved by an election - a classic, if expensive, way to buy some time.
Once the Assembly votes were counted at the start of March, there were then only meant to be three weeks to broker a new Assembly before it had to be dissolved.
April still came and went without a breakthrough. Brokenshire insisted he might be forced to consider direct rule if a deal hadn't been done by the time Westminster returned from its Easter recess on April 18.
As that date neared, no prizes for guessing, he extended the deadline further, stating that "some further progress has been made", adding that "the parties will have a final opportunity after Easter to reach agreement". Does he know any more what the word "final" means?
As it happened, he was spared from having to stand by his word by the surprise announcement of a general election. The results of that led into extended negotiations between the DUP and minority Tory Government, which complicated matters, while in Dublin a new Taoiseach and Minister for Foreign Affairs provided more distraction and delay.
By this point, another deadline had been imposed. That was 4pm on Thursday, June 29 and it came with threats of "profound and serious" consequences if agreement was not forthcoming. Make that two more words of whose meaning James Brokenshire is evidently unaware, because that one passed without agreement, too.
The deadline was extended to the following Monday, which the spokesman for the Secretary of State described thus: "We are now allowing the parties the space to continue the discussions." It sounds so much nicer when you put it like that, doesn't it?
They weren't admitting that deadlines meant diddly squat. Not at all. They were just giving the parties a bit more "space". Over that weekend, Irish Government sources whispered that a deal was very close and that the parties were down to discussing "technical details".
Sinn Fein president Gerry Adams warned everyone not to get their hopes up. To be fair, he was right. By Monday it had all fallen apart and Brokenshire went to the House of Commons to announce that he was definitely putting in place some groundwork that might, one day in the future, allow him to set a budget for Northern Ireland. But not just yet. In the meantime he granted the parties more time to come together.
The coming weeks brought suggestions that the British Government was preparing "new tactics", perhaps even appointing an outside mediator, or dragging the parties to a venue outside Northern Ireland. All that came to nothing, so talks commenced in September with a new format, as Sinn Fein and the DUP were packed off alone to thrash things out.
That didn't work either. Nor did a flying visit from former US President Bill Clinton. Now another Manic Monday has come and gone, Halloween is history and there's still no sign of an end to the stalemate.
Even the Brexit negotiations are going better than the talks at Stormont. That's how bad things have got. It's worth remembering that it took just six months to finalise the entire Treaty of Versailles at the end of the First World War, bringing an end to what was, at the time, the bloodiest conflict in human history.
Admittedly, the Great Powers didn't make a great fist of it, since an even more horrific war broke out again within 20 years of its implementation, due partly to the punitive conditions imposed on Germany.
It was also only signed after the Allies threatened to march across the Rhine if the government in Berlin did not immediately agree to the terms, so it wasn't what you'd call consensual. But it's still astonishing that the political process in one small corner of these isles has been held up for longer by a squabble over a stand-alone Irish Language Act and other footling bits and pieces.
Work expands to fill the time available to do it and, in the case of the restoration of Stormont, the time available appears to be limitless. Even if the Secretary of State does set a budget at Westminster, that doesn't mean the talks will end. How can they?
Direct rule is not a long-term option. Is that the problem? Those round the table at Versailles had work to do to rebuild the continent after the Great War. They weren't prepared to waste their time arguing over trifles.
In Northern Ireland, by contrast, talks have become the real business of politics. The British Government couldn't make it more obvious that it doesn't want to take on direct rule. Hence the litany of final chances.
As long as deadlines mean nothing, local politicians are set free to dig in their heels and fight tooth and nail for every tiny victory over one another.