Tom Devine: Today is the most important date since 1707 Act of Union

THE agreement signed today marks the end of the twilight war before the real debate begins on the historic choice which confronts the Scottish people in 2014.

Until now there has been more sound bites and rhetoric than serious discussion.I would hope that after today’s historic event we will move on to a powerful clash of ideas, opinion and analysis on the fundamental issues, befitting the most important decision which this great nation will have made in over three centuries.Even if that occurs, however, there will remain plenty of unknowns as the people of Scotland contemplate whether to vote yes or no.Above all, on the central question of the likely health and shape of a post-independence Scottish economy, even the most gifted economic thinkers can only hazard a guess on what might be like in the future.The same uncertainty prevails around the possibility of a vote for the status quo.How will Scotland within the Union after 2014 fare in the expected long years of continuing austerity, with rigorous controls imposed on the public finances and the conviction in Westminster that the bogeyman of resurgent Scottish nationalism need no longer be appeased?

The unprecedented nature of the momentous decision to be made in 2014 also fascinates the international community.Hardly a week goes by without a media organisation from across the world making contact with me in Edinburgh University to enquire why this nationalist dynamic has developed and what might be the possibilities for a winning vote for independence in the referendum. To that second question I tend to offer the lame excuse: ‘The future is not my period’.

Scotland will indeed be a focus of global interest over the next two years and especially as the debate reaches its historic climax.This is hardly surprising.The Union partnership between England and Scotland made the British Empire from the eighteenth to the first half of the twentieth century.The greatest ever territorial imperium on earth has influenced and helped to fashion the language,culture, religion, economies and the peopling, by mass emigration, of numerous countries in almost every continent.It is hardly surprising that the possible constitutional unravelling of the Great Britain which created that empire now attracts the attention of the world.

There is a local irony, however, at the heart of this potentially epic story.

The collapse of most previous unions between European nations in the last few centuries have usually come about by overwhelming articulation of the popular will, sometimes reinforced by violence.The Soviet Union, the Irish Republic and the Scandinavian countries are prime examples of this outcome in history.

The narrow victory of the SNP in the last Scottish Parliamentary elections, which triggered the move towards a referendum did not come about because of a national demand for independence.Less than a third of the electorate favoured that option at the time.Rather the success was based on the perceived competence of the previous SNP minority administration, the attraction of its social,health and educational policies and, above all, the electoral failure of the two major unionist parties,the Conservatives and Labour.

The irrelevance of the Conservatives has been a fact of life in Scottish politics since the 1990s.The new and telling factor was the decline of Labour.If Scotland votes for independence in 2014, future historians may consider a main reason to have been the weakening grip of the main unionist party,Scottish Labour,on the country’s political loyalties and not necessarily the result of a new and massive commitment to the SNP.An end to a three hundred old Union brought about by the ebb and flow of Scottish domestic politics? That would indeed be an irony of truly historic proportions.

• Tom Devine is professor of history at the University of Edinburgh.