One idea that developed in popularity among some on the left is this idea of the "separated brethren" - namely that divisions between Labour and the Liberal/Social Democrat Alliance ensured that Thatcher achieved massive majorities in June 1983 and 1987. And, with logic similar to the let's-add-together-the-Conservative-and-UK-Independence-Party-vote, it is assumed that if only Labour and the Alliance had co-operated, then Thatcher's tenure would have been brought to an end and she would - at best - be remembered as a one-termer.
Around the time of the May 2011 referendum on the Alternative Vote, the BBC looked at what impact it would have had in the 1983 and 1987 elections, and we see that it hits Labour but is fairly neutral to the Conservatives. Surely, if the "separated brethren" idea was true, then AV would have led to a collapse in the number of Conservative MPs as Labour and Alliance voters give their second preferences to each other. And when you look at the data, you find that Alliance voters would be more likely to give the Conservatives their second preferences.
And consider the 1987 election. In Labour's Shadow Cabinet there were Roy Hattersley as Deputy Leader of the Opposition/Shadow Chancellor of the Exchequer, Denis Healey as Shadow Foreign & Commonwealth Secretary, Stan Orme as Shadow Energy Secretary and John Smith as Shadow Trade & Industry Secretary. Outside of the Shadow Cabinet were John Morris as Shadow Attorney-General and Peter Shore as Shadow Leader of the Commons. All of these had served in a Cabinet with Owen. Orme - along with Michael Meacher, Shadow Health & Social Security Secretary - had served alongside Owen as ministers at the Department for Health & Social Security.
Also bear in mind that you weren't to know that the Social Democrats' Roy Jenkins was to lose Glasgow Hillhead to Labour. Healey and Shore had served in Cabinet alongside Jenkins, not only in the 1970s but in the 1960s as well. Brynmor John, Shadow Agriculture Minister, had been one of Jenkins' ministers when he was Home Secretary. And indeed, the period from November 1967 to October 1969 saw Jenkins as Chancellor of the Exchequer and Shore as Economic Affairs Secretary - with the Department for Economic Affairs having been set up as some sort of counterweight to the Treasury.
In Labour demonology there is a special place for defectors. To ask a Labour MP to take a post outside the Cabinet to ensure Steel can be a Cabinet minister is one thing - but to ask a couple of Labour MPs to do this to enable Owen and Jenkins to return would be a completely different kettle of fish.
There was a perceptive article in The Times by Philip Collins (£), where he notes:
The crucial fact here is that the Labour Party is a tribe with its own rituals, incantations and heresies. There is no crime worse than betrayal of the tribe and Labour enjoys the burning of the effigies of its traitors. The turncoats of 1931, Ramsay MacDonald and Philip Snowden, who joined a national coalition, cast a long shadow in a party that asks for doctrinal purity. The latter-day sinners are the Gang of Four who broke away to form the SDP in 1981. In Who Goes Home?, his fine memoir of the time, Roy Hattersley distils the emotional bond of his party when he says that even if he had known that Labour was doomed, he would have chosen to go down with the ship.
In this version of the loathing, Lib Dems are seen as the descendants of treachery — the very existence of the party is the product of an original sin. The SDP split the vote on the left and allowed free rein to Mrs Thatcher. That left Labour moderates angry that they were left to fight militant entryists while some of their talented colleagues set about failing to break the mould of British politics.
Today saw the Shadow Cabinet reshuffle and - as Dan Hodges notes in the Daily Telegraph - there is no place in Labour for the Blairites. I mentioned a few weeks ago that if you look at Labour now, it is hard to believe that former Prime Minister Tony Blair was once its leader.
If the Blairites feel that there is no place for them in Labour now, then there is one thing they could do - which is to consider another home. And if they approach the Conservatives, then they should be told where to go.
And that place is the office of Don Foster, the Liberal Democrat Chief Whip and Government Deputy Whip.
You may be asking what sense is there in the Conservatives telling potential defectors from Labour to see the Liberal Democrats instead.
There surely would be the short-term publicity in a former Labour minister declaring they are now a Conservative MP. And "short-term" is the operative word here. The Conservatives need to plan long-term. As Collins' piece noted, even over 30 years after the creation of the Social Democrats, the Liberal Democrats are seen as the "descendants of treachery". So, what would be the impact of fresh treachery? What would happen if former Labour ministers on the right of that party defected to the Liberal Democrats?
Principally, it would make the Liberal Democrats toxic to Labour. If a Labour/Liberal Democrat coalition had been formed after the May 2010 general election then - with the exception of Tom McNally, Deputy Leader of the Lords and Minister for Justice - there would be no former Labour MPs involved. But just imagine a hung Parliament after the May 2015 general election, where there were some sitting Liberal Democrat ministers who had once been Labour MPs. Who had fought re-election campaigns against their old party. Wouldn't that make a Labour/Liberal Democrat coalition just that bit harder to form, and leave no option for the Liberal Democrats - unwanted by Labour - other than keeping a Conservative-led Government in power?