Social democratic party positions on the EU: The case of Brexit.

In recent years, social democratic parties have been confronted with the rise of second dimension issues. These issues often see social democratic parties facing a choice between competing portions of their own electorate. A particularly prominent second dimension issue is that of the EU: should social democratic parties take pro or anti-EU positions? I look at the case of the UK as an instructive example of this debate. I estimate a narrow counterfactual, simulating how the Labour Party's vote share and seat count would have changed as its position on Brexit changes. I call this counterfactual narrow because I only consider the effect of these position changes on vote choice and turnout, and not any broader consequences. I run two simulations to compare the implications of pure proximity and proximity-categorisation models of vote choice. I generate seat predictions from the simulation results by using Uniform National Swing and Uniform Regional Swing. Broadly, I find that being pro-Remain clearly benefited the party in terms of votes, but that results are more mixed in terms of seats. [ABSTRACT FROM AUTHOR]