What factors led to the surprise defeat of the Colombian peace referendum? Descriptive analyses suggested a link between support for peace and the experience of violence, but economic conditions and political support for incumbent parties also affect electoral outcomes. Here we use Bayesian hierarchical models to test links between referendum result and previous violence victimization, economic conditions, and support for Centro Democrático (the main party opposed to the peace agreement). There was lower support for peace in the Andean region, and departments with lower support had higher unemployment and growth in GDP. Support for the opposition was the dominant covariate of decreasing support for the peace accords, while previous violence victimization increased the percent vote for peace. Regional variation in baseline support for the agreements will be critical during implementation of the newly revised accords, and the mobilization of the opposition shows partisan engagement determined the referendum outcome.