To anyone old enough to remember the 1990s, the latest outbreak of infighting has an air of almost comfortable familiarity, neatly evoked by Jonathan Freedland when he tweeted 'Tory row on EU, Ken Clarke on radio - and is there honey still for tea?'.
Tory splits on Europe have been a central theme of British politics for a generation, providing moments of high drama and low farce, but John Major's troubles two decades ago may not be the closest analogue to David Cameron's problems now.
For those of us who closely followed another un-ending political saga of recent decades, the Irish peace process, the fate of David Trimble's Ulster Unionist Party (UUP) may be a more instructive parallel.
At first glance, of course, nothing could be more sui generis than Northern Ireland politics, and the fate of a political party whose modern history took place in the midst of the most violent political conflict in post-war Western Europe.
Yet the commonalities are also clear. The two parties have a shared heritage, their common unionism being a key part of the political formula which enabled parties rooted in the county families of the landed gentry to make the transition to the age of democratic mass politics, through a social imperialism which earned the support of a cross-class constituency in Joseph Chamberlain's Birmingham as much as in James Craig's Belfast.
By the 1960s, both parties had to adjust to an era in which such British exceptionalism no longer seemed tenable. The first efforts at reform were led by traditional leaderships. The aristocratic Tory, Harold MacMillan presided over decolonisation and the first attempt to join the European Economic Community. In Northern Ireland, the aristocratic unionist Terence O'Neill sought to build modest links with Dublin, only to found himself challenged on the right by ambitious ministers in his own party, and by the street politics of Ian Paisley.
After O'Neill's downfall amid the turbulence of 1969, some of his moderate supporters joined the Alliance Party, but the greater threat to the Ulster Unionists was Paisley's Democratic Unionist Party (DUP), founded in 1971.
And this is perhaps the most important point of the parallel. For decades, the decisive struggles on the British right, between wets and dries, europhiles and euro-sceptics, modernisers and traditionalists, took place under the umbrella of the Conservative party. Only now are the Tories facing an insurgent rival on their right flank, the challenge that Ulster Unionists have lived with for a generation.
In the 1980s, under James Molyneaux the Ulster Unionist Party was able to maintain a veneer of stability only because of complete political stasis.
As soon as the Ulster Unionists faced unavoidable choices, the divisions returned. Like David Cameron, David Trimble led his party into a power-sharing agreement which many in his party regarded as a betrayal. Althought the circumstances were very different, the parallels are irresistable.
Like Tories today, unionists cast about for more palatable alternatives with a wilful disregard for political realities. Then it was voluntary coalition, today it is minority government. Like Cameron, Trimble negotiated those realities with enough pragmatism to annoy hardliners, but without enough conviction to give heart to moderates.
The DUP were emboldened, just as UKIP are today. The Ulster Unionists sought to see off the threat with hardline rhetoric. The old adage that "you can't out-Paisley Paisley" went unheeded just as the newer injunction that "you can't out-Farage Farage"was ignored at Eastleigh.
Some Ulster Unionists looked on the DUP more as fellow travellers then as deadly rivals. Jeffrey Donaldson's calls for unionist unity are echoed almost word for word a decade later by Nadine Dorries' calls for right-wing unity. Dorries seems no more cowed by losing the whip than Donaldson did.
Both the older parties are exposed to the Trojan horse of unity by their nineteenth century collegiality. Trimble had to rely on Sir Josias Cunningham to sustain majority support in the Ulster Unionist Council, in which some members were closer to the DUP. David Cameron has to look over his shoulder at Graham Brady's 1922 Committee, where some of the same MPs who want the right to a UKIP endorsement can put down signatures seeking a leadership challenge. The DUP exploited such openness ruthlessly, and UKIP looks capable of doing the same.
Jeffrey Donaldson, Trimble's chief Ulster Unionist critic is now a DUP MP. Few would be surprised to see Dorries or another Tory right-winger make a similar transition to UKIP. But the UUP suffered almost as much from the defections of moderates to the centrist Alliance Party. The defection of a coalition enthusiast, such as say Nick Boles, to the Lib Dems, might be the most dangerous warning sign of all for the Tories.
The fate of the UUP shows the dangers that face a hegemonic party that finds itself challenged on two fronts. The point of disintegration comes when every tack towards one wing causes more problems on the other than it solves. A broad church can soon become a collection of warring sects held together only by nostalgia and inertia. Recent comments from Geoffrey Howe and Matthew Parris are ominous for Cameron in this respect.
One way to avoid such gyrations is to do as little as possible, a natural strategy for the relaxed rentier layer of the Tory leadership, but one which the Conservative right has repeatedly foiled.
A decade ago, it was Blair and Clinton who sought to 'save Dave', now it is Merkel and Obama. Such hand-holding once allowed UUP hardliners to argue that their disloyalty was strengthening their leader's negotiating position, just as some Conservative MPs now do. It is an argument that has been shown to be hollow.
For a decade, the crisis in the UUP was the bread and butter of Northern Ireland political journalists. That period ended, not because the crisis was resolved, but because the Ulster Unionists had become dispensible.
A stable settlement only occured after other parties had waited out and worked around the Ulster Unionists. Lord Howe's comments in particular suggest a similar prospect could confront the Conservatives.
Such a conclusion might seen as under-estimating the latent strength of one of the world's most successful right-wing parties, but the willingness of much of the Conservative right to act as a Trojan horse for UKIP indicates that the rot has set in deep.
This is not necessarily a rosy scenario for the left. If the UUP provides a precedent for Conservative failure, the corollary is that the DUP provides one for UKIP success. And UKIP's eclipse of the BNP may not be a reason for long-term optimism. The DUP has long won urban loyalist votes in Belfast, but retains a disconnect from the urban working class that has enabled a variety of right-wing forces to incubate the recent flag protests.
One worrying lesson from Northern Ireland, then, is that division on the right may yet mean trouble for everyone else.