In this paper, we investigate the phenomenon of party switchers in the Canadian House of Commons. With the most extensive dataset on party-switching MPs (1867–2015), we answer the following questions: What are the electoral trajectories of party switchers? Have their prospects changed over time? We assess whether the historical dynamics of the Canadian party system explain changes in the incidence and fate of party switchers since 1867, hypothesizing that both the rate of party switching and the electoral fortunes of floor crossers decline over time. The evidence accords with our second hypothesis more strongly than our first. Party switching has become slightly less common, but the electoral consequence has become much more severe.