How (and when) does party matter? Explaining MPs’ positions on assisted dying/assisted suicide

Abstract While the legalisation of assisted dying/assisted suicide (AD/AS)1 has enjoyed sustained public support for several decades, Parliament has repeatedly voted decisively against legalisation. This article explores this parliamentary deviation from citizens’ preferences by explaining what shapes MPs’ positions on this free vote issue and, in particular, how (and when) party matters in shaping these positions. It considers both the last Commons vote in 2015 and developments up to July 2024,2 thus avoiding a snapshot analysis of a single moment in time. It finds that while party mattered in the 2015 vote, it was one of many factors that mattered, and was not obviously the most important. However, developments since 2015 suggest that party is likely to play a greater role in the next vote, which is expected in the current parliamentary term.