As LP Hartley put it: "The past is a foreign country: they do things differently there." Not in Northern Ireland they don't. The present in Northern Ireland is just the same as the past and we don't do things differently.
In July 1973, Brian Faulkner warned of the dangers of creating power-sharing structures "which were designed to reconcile irreconcilables in Government". That's precisely what the DUP and Sinn Fein did in May 2007.
They didn't construct a deal built around compromise and mutual understanding: they constructed it around mutual veto, carve-up, petition of concern and the ability to "stop the other side" rather than moving forward together.
And that's why their relationship is one of permanent, knuckle-dragging stalemate: a battle a day; a grudge a day; an attack-dog speech a day; an it's-all-your-fault Press release a day.
In September 1973 Prime Minister Edward Heath noted "as long as the Northern Ireland parties look to external powers to take decisions, they will never come to grips with responsibilities".
Yet, 40 years on – and almost seven years into the DUP/Sinn Fein deal – Richard Haass (left) was the latest of a long line of 'outsiders' invited to play the role of honest broker. Last week there was even talk of someone being brought in to help the parties sort out the ongoing costly standoff over welfare reform.
And hardly a week goes by without one party or another lifting the phone and demanding a meeting with the Prime Minister, Taoiseach, ex-President Clinton or, indeed, with anyone who is prepared to listen to their latest whinge.
Both the DUP and Sinn Fein insisted that they could deliver stability and strength to the political institutions. They argued that the failure of the UUP and SDLP to keep the Assembly and Executive on the road was because there were too many loose ends that needed to be tied up.
In May 2007 Gerry Adams and Ian Paisley claimed that those ends had been tied up and that they had negotiated a deal between them that would provide "stable, strong, accountable Government for Northern Ireland".
That's not what they meant, of course. What they negotiated was a deal that would increase polarity and channel those who could be bothered to vote into us-and-them camps controlled by the DUP and Sinn Fein. Their deal was a blinkered, self-serving, self-preserving deal designed to keep them at the helm for as long as was possible.
They had replaced one-party rule with one-party-for-each-side rule.
But – and it didn't take long for them to discover it – there is a thumping big problem at the heart of their deal. While it is true that they can encourage the polarity and finger-pointing which suits both their electoral purposes very nicely, thank you, it has not been possible for them to exercise power, let alone share power.
And when power cannot be exercised, then government – in the sense that it is normally understood – is not possible.
We don't have government in Northern Ireland. At best, it can be described as an administration: dealing mostly with the issues and bits-and-bobs of everyday political business that could just as easily be done under direct rule.
Ministers do their own thing, accountable only to their own party leader and incapable of being sacked by a vote of no confidence in the Assembly. There is nothing resembling a vision for Northern Ireland, because none of the parties, including the smaller ones, has a shared vision for Northern Ireland.
Indeed, the only thing the parties have in common is a fondness for blind-eyed optimism, excruciating cliché and an inability to understand that the non-stop chanting of the "sure-it's-better-than-it-used-to-be" mantra is not actually a substitute for government.
What is lacking here is the ability to exercise power: the inability to construct and promote a Programme for Government which addresses key socio/economic/cultural/historic issues and provides collectively agreed policies; the inability for incisive Assembly debate which doesn't, often within minutes, descend into members of the same Executive attacking each other for bad faith and poor judgment; the inability to convey the impression that the Executive and Assembly make a real, positive difference to the everyday lives of everyone here.
In June 1993 Norman Lamont gave this withering critique of John Major's Government: "It gives the impression of being in office, but not in power." That's precisely the impression given by Peter Robinson and Martin McGuinness.
Some people argue that dissident republicans and discontented loyalists pose a real threat to the political process. They are wrong. The greatest threat to the political institutions stems from an inability to exercise power and make decisions; the growing public impression that nothing is changing in Northern Ireland; a massive disconnect and disengagement by civic society from the institutions; a seemingly unstoppable downward plummet in voter turnout; and the deliberate nurturing of an "us-and-them" society.
Northern Ireland is in a very dangerous place at the moment: a place where the key parties don't trust each other and where the majority of people neither expect nor predict improvement. The collapse of the institutions is not inevitable. But it is much closer than most people realise.
Meanwhile, the parties fight the old battles, rehearse the even older grudges and, like some sozzled Pollyanna, pretend that all is well.
It isn't. And there is very little time left to fix it.