Harold Wilson had a referendum on the UK membership of the then Common Market not because he had discovered a new principle of public engagement in a major decision about the future of the country, but instead to hold his warring party together at the top. Pro and anti could still be good mates as they were allowed to campaign on opposite sides rather than battle to have the Labour party opt for either yes or no. That meant the battle was transferred out of the Labour party and into the nation as a whole. 40 years on and another referendum looms. This time, David Cameron has, in effect, told the Tory anti-Europeans in government that they must travel with him on his ship or jump overboard.
The referendum will in effect be about the principle of membership of the EU. The details of any renegotiation will be of secondary importance. That may be helpful to Cameron who may come back from his negotiations with changes that are somewhat limited and need to be spun as major concessions. For most Tory Eurosceptics, nothing short of a withdrawal is acceptable.
So where does all this leave the Conservatives? The starting point is that they are currently the dominant political party. The key UK-wide opposition parties on the other hand have been significantly weakened by the election last month. Can the Conservative coalition of pro and anti Europeans hold together over the next two years if senior figures of the anti side are restrained from speaking against Cameron's side? Will the demand to speak out on Europe result in resignations? If that does happen, the divisions that dominated the Tories in the 1990s will be back in play.
If however, Cameron comes back with a renegotiation, however minor, and wins a referendum, with or without the backing of his anti-Europeans, his dominance over his own party will be complete. Sadly for him, he has already announced he will not lead the Tories into the 2020 election. Maybe the Tories will do a UKIP style rejection of his retirement though I think that is unlikely. It will mean the Conservatives will go into the next election with a new leader but one who could benefit from a Cameron referendum victory.
Cameron, having crushed Labour, Lib Dems and UKIP in the 2015 general election, could have started another long period of Conservative rule. And in such a scenario, the anti-European headbangers will have been crushed as well. It makes the mountain opposition parties need to climb even harder to negotiate.
It is of course a high risk strategy for Cameron. If it goes wrong, if he comes back with nothing, and the referendum is lost, he will rapidly be out of office, the Tory right will be in control and we will be out of the EU. Not a pleasant thought. If the high risk strategy works however, the opposition parties will face a rejuvenated Conservative Party led from the centre ground. It may be the centre right but nevertheless, it's still the centre ground. If Labour opts for the comfort zone of Andy Burnham, just as they did with Ed Miliband, the Tory dominance could last for many years.