A composite image made up of the manifestos from the UK 2017 General Election

Navin Kartik, Richard Van Weelden, and Stephane Wolton argue that vagueness on the campaign trail can lead to better governance as it gives the election winner flexibility to adapt policy to changing circumstances. However, electorally advantaged candidates are almost always more ambiguous than their opponents and over-ambiguous from the voters’ perspective.

Vagueness vs Clarity

It is all too easy to find comments lamenting the vagueness of electoral campaigns:

Trump favors strategic ambiguity — on everything. He says he doesn’t want to be too explicit about his foreign policy because it will tip off our adversaries about our intentions. He apparently doesn’t want to tip anyone off at home, either” – Rich Lowry, 13 May 2016

In the fight against Islamism like anything else, [Emmanuel] Macron cultivates ambiguity” – François Fillon, 20 April 2017

Where benefit cuts are proposed, they are largely unspecified (Conservatives), vague (Liberal Democrats) or trivially small relative to the rhetoric being used (Labour)” – Institute for Fiscal Studies, 28 April 2015

[Barack Obama] delivered a speech last night that was much more about grinding out a narrow victory (…) than about offering a detailed and comprehensive agenda for the next four years” – Ryan Lizza, 7 September 2012

Voters, however, do not seem to punish candidates’ ambiguity. In fact, politicians who choose vagueness over clarity often appear to benefit electorally. Recent suggestive examples include Donald J. Trump in the U.S. and Emmanuel Macron in France. (For a more rigorous assessment of the consequences of candidates’ ambiguity, see Michael Tomz and Robert P. Van Houweling, “The Electoral Implications of Candidate Ambiguity” ).

How can we understand these patterns? Why might ambiguity be appealing to voters (and candidates)? Do elections create incentives for politicians to be only as ambiguous as voters desire?

Making sense of vague campaign promises

In a forthcoming article in the American Journal of Political Science, we propose a theory to make sense of candidates’ vague campaign promises. We posit that policy-relevant information is revealed to the elected politician after the election. Commitment during the campaign to only a broad set of possible policies (rather than a single policy) permits an elected politician to implement a policy that is better tailored to new circumstances as they emerge.

The resulting flexibility is beneficial both to voters, as everyone benefits from appropriate policies, and to candidates, who can tailor policies not only to the circumstances but also to their own ideological preferences. Due to the ensuing “policy bias,” as it is referred to by political scientists, voters may not want to give candidates too much flexibility. That is, for each candidate, there is an optimal level of ambiguity for voters, which depends on that candidate’s ideological alignment with voters.

Voters give moderate candidates more flexibility

But voters do not choose candidates’ platforms; the candidates themselves do! Do elections lead to the optimal level of ambiguity?

The answer turns out to be no, quite generally. Only when candidates’ ideological preferences are “symmetric” or very extreme do voters obtain the optimal degree of ambiguity. Otherwise, the more moderate candidate—who tends to win the election—is overly ambiguous. Voters prefer to give more flexibility to more moderate candidates, and a moderate candidate can propose a vague platform that is more attractive to voters than the more precise platform of an extreme candidate. Ultimately, a moderate candidate can exploit his/her electoral advantage to obtain more flexibility than voters would ideally like to give him/her.

Our work thus predicts that electoral competition does not sufficiently discipline politicians when one candidate is viewed as more moderate than his/her competitor. What does this conclusion entail for the forthcoming 2017 general election in the U.K.? Several studies document that Tories and their leader Theresa May had a clear advantage over their competitors when the election was announced, be it in terms of approval ratings or the handling of many issues such as Brexit negotiation.

Our theory suggests that the Conservatives are likely to exploit this advantage and offer less-detailed policy proposals than their opponents. Theresa May’s vastly shorter manifesto than her predecessor, David Cameron’s – 25 pages rather than 120 – is thus unsurprising, albeit discouraging. While some vagueness is efficient, the extent of it should be met with cynicism by voters and pundits alike.

Navin KartikNavin Kartik is professor of economics at Columbia University, New York.




Richard Van WeeldenPortrait photo of Richard Van Weelden is assistant professor of economics at the University of Chicago.




Stephane WoltonPortrait photo of Stephane Wolton is assistant professor of political science at the London School of Economics, Department of Government.



Note: this article gives the views of the authors, and not the position of the LSE Department of Government, nor of the London School of Economics.