Philip Cowley is Professor of Politics at Queen Mary University of London, UK. He is (with Dennis Kavanagh) the author of The British General Election of 2017, published today by Palgrave.

The British General Election of 2017 is the definitive and authoritative account of one of the most dramatic elections in British history. Drawing on hundreds of interviews, with unparalleled access to all the key players, The British General Election of 2017 offers a revelatory guide to what really happened. Order your copy, or enter to win a free copy, here. Terms & Conditions apply.

In their introduction to The British General Election of 1945 – the volume that began the so-called “Nuffield” election studies – R. B. McCallum and his co-author Alison Readman began with the Duke of Wellington’s observation that you could no more describe a battle than you could describe a ballroom. ‘Still less’, they remarked, ‘can you describe a general election.’ The only thing that was certain about a general election they said was: ‘It is not simple.’ 
Their comments certainly apply to the 2017 contest – which was the subject of the twentieth volume in the series that McCallum and Readman began. It was a particularly difficult election to write about. Once an election is over and it is possible to talk openly with the participants, it is usually the case that for all the complexity in any election, there is a consensus about what happened. For the most part, staffers and politicians on one party agree with their rival counterparts about why one campaign struggled and why the other succeeded. There are nuances and differences—sometimes genuine, and a result of the different perspectives of participants, sometimes driven by self-interest or partisanship—but these are often quite marginal. When it comes to the fundamentals, there is normally little disagreement.
This was not true when writing about this election. Once we move beyond the merely descriptive—that is, the Conservatives had a huge opinion poll lead, which they proceeded to lose—there is little agreement about what happened in the 2017 general election or, at least, why it happened. Perhaps most striking, there is no intra-party consensus on these questions. There are at least two versions of the Labour campaign, both passionately believed, along with a similar number of views of the Conservative campaign. During the more than 100 interviews which we conducted for the book the phrases used by insiders about supposed comrades or colleagues were often much cruder, and more industrial, than those about their supposed opponents. This was both a problem for us, as authors, but it was also a telling observation about the nature of the various campaigns, which were riven by intra-party disagreement. 
The other reason the contest was so difficult to write about was because of the result. Had it been the outcome which almost everyone – including most inside the Labour Party – expected when it began, it would have been easier to describe and analyse. Yet Labour’s surge in the polls appeared to challenge so many of the things we thought we knew about elections. One of the truisms of election campaigns is that the formal, ‘short’ campaign does not matter very much. For all the sound and fury, campaigns rarely affect election outcomes. The party ahead in the polls at the beginning is almost always ahead at the end, often by roughly the same amount, and when this is not true, it is usually because of errors in the polls rather than any change in the standing of the parties. All the things that obsess journalists and excite politicians—the leaders’ tours, the debates, any ‘gaffes’, the parties’ manifestoes—are all electorally trivial. When a party wins or loses an election, it is not because of what it did in the weeks of the campaign, but because of more fundamental perceptions about the parties, their policies and their leaders which have built up over the preceding years of a parliament, or in some cases even longer.
The 2017 campaign presented a serious challenge to such a view of politics, because what happened between 18 April and 8 June 2017 profoundly mattered and had a material impact on the outcome of the election. Labour began the campaign staring down the barrel at one of its worst election performances in its history, but ended just a few thousand votes away from Downing Street. 
Yet this can be taken too far. For all Labour’s impressive progress, the party ahead at the beginning of the campaign remained ahead at the end – and the party ahead at the beginning of the campaign again went on to form the government. Nor should 2017 be seen as a complete dismissal of other well-rehearsed maxims about the importance of competence and leadership—what political scientists call ‘valence’ politics. Jeremy Corbyn’s ratings improved dramatically during the campaign, but even at the end he still trailed Theresa May as the person seen as making the best Prime Minister. For all that Labour’s standing improved, the final polls still showed the Conservatives ahead on economic competence and on their ability to handle the most important issue facing the country. In other words, the party led by the person considered the most competent, which was ahead on the economy and on the issues considered most important to voters, went on to form the government. 
To note this is not to downplay the transformation in Labour’s standing. It affected the outcome significantly, far more than almost everyone expected. As a result of the campaign, Britain ended up with a minority Conservative government rather than a majority Conservative government, let alone one with a landslide majority – but it did not end up with a Labour government. Labour may have won the campaign; it did not win the election.