The two David Camerons

It has taken a long time to get here, but at last David Cameron has delivered his big Europe speech. Judging by the generally broad grins of Tory Eurosceptics being wheeled out on rolling news channels, he at least seems to have been successful in appeasing elements of his party. Whether Cameron's strategy is ultimately successful though - and how it will influence his page in the history books - is an entirely different matter.

It has now become very apparent that there are two very distinct David Camerons. What is interesting about today's events is that both of them were prominently on display. The first is an idealist, a man who sees himself as the visionary leader of a one nation party rooted in the liberal-conservative centre of British politics. This version of Cameron thrives on big gesture politics, and has been most evident during the 2006 leadership campaign, and then again when making the coalition offer to the Liberal Democrats in 2010. In contrast, the second David Cameron is more instinctively conservative, risk-averse and focused on relatively short term electoral and partisan calculations. This version of David Cameron has perhaps been most evident in his dealings with his own party.

That both David Camerons played a role today is evident in the rather prescient comment made in The Guardian liveblog on the speech that while this was probably the most Eurosceptic speech ever made by a British Prime Minister, it was also probably the most pro-European speech made by David Cameron. And while short-term electoral and partisan calculation are clearly involved in what Cameron has argued, there is also a more idealistic idea being articulated as well - namely the desire to win an in-out referendum (after a successful renegotiation process, obviously), in the process laying to rest the most virulent strand of Tory Euroscepticism that has dogged Conservative leaders for a quarter of a century, and settling the European question for at least a generation.

What is already very clear though is that this is a massive gamble for Cameron and for Britain. European leaders and foreign ministers are queuing up to say that what Cameron suggested today is unacceptable. One interesting insight into the potential pitfalls faced by Cameron now is found in David Marquand's Britain Since 1918, an excellent history of the British constitution that I have just finished reading. Marquand's arguments are instructive on two levels as to how this situation might develop.

First, Marquand notes that British diplomacy has traditionally failed in Europe because it has not appreciated the weakness of its position. This goes back as far as the original European Coal and Steel Community, and Britain's refusal to join, followed by subsequent attempts to join the EEC under Macmillan. The error made here was to attempt negotiations from ground up, with Britain's equal status assumed. This neglected the fact that other members of the EEC had already been through an extended process of negotiation while Britain stood aloof. It is no coincidence Marquand argues that the British application was only successful when Heath took a new approach - broadly accepting the rules of the club as fixed in order to win admission.

But Marquand also offers a possible course of action for Cameron. After all, we have been here before. Prior to the two election of 1974, Harold Wilson's Labour Party promised a renegotiation of Britain's membership of the EEC if elected, followed by a referendum on the outcome. Much like Cameron, Wilson claimed to be pro-European, and took this stance to appease the ideologues in his own party. In practice though, Wilson's renegotiation amended tiny details of the Britain's relationship with the EEC (tariff exceptions for the import of New Zealand butter and suchlike), yet was haled as a massive coup by Wilson. Whether Cameron could pull a similar trick is open to question, but this might be one possible course of action open to the Conservatives after a 2015 election.

But this is a dangerous game of political brinkmanship. And indeed, this may prove to be the supreme irony of Cameron's premiership. Writing about recent history, Marquand reminds us just what a constitutionally radical government Labour offered, especially between 1997 and 2001, when devolution occurred and House of Lords reform took place. This constitutional reform was far from perfect; indeed, in some ways it was downright flawed - the West Lothian question rumbles on, unaddressed, and House of Lords reform remains a half finished work-in-progress. Yet, in broad terms, Labour undoubtedly achieved what it set out to do.

Labour were followed in office by Cameron, the self-confessed constitutional conservative. Yet, thanks to one referendum, he might be the unionist who oversees the dissolution of the union, and thanks to another referendum, he might be the premier who, while doubtless a sceptic, claims to be in favour of Britain's membership of the European Union, but leads Britain out of the EU. It is one thing to achieve constitutional goals with and leave some mess behind, as Labour did. It is quite another to make a mark on the history of the British constitution wholly through unintended consequences.