Tactical Voting and Electoral Pacts in the 2019 UK General Election

Abstract

The Brexit cleavage continued to define politics in the 2019 general election. This posed a challenge for parties and voters on each side of the debate: how to coordinate in favour of their side in each seat. In this note, I examine the extent to which party (electoral pacts) and voter (tactical voting) coordination affected the outcome of the 2019 general election. On the voter side, I find that tactical voting was only slightly more prevalent than in previous election cycles. On the party side, I find that neither the Unite to Remain pact nor the Brexit Party’s withdrawal of candidates against incumbent Conservatives noticeably affected the results. Holding the structure of preferences in 2019 constant, Labour would probably have won a handful of additional seats in England and Wales (three on average but only one clear gain) by joining the Unite to Remain pact. The effect of the pact is limited because Labour successfully won over many Remain supporters from the other parties during the campaign. This meant that voters of the other Remain parties were only modestly more likely to prefer Labour over the Conservatives by the end of the campaign, and the pool of minor party voters was generally small in Labour’s target seats. The Liberal Democrats would have received around eight additional seats if Labour had joined the pact (again holding preferences constant).