Vote buying persists despite democratic safeguards. This article explains why: brokers enforce deals through published results only when monitoring small voter groups is feasible.

Key Finding: Brokers target compliance in small voting blocs to sustain vote-buying networks.

Evidence from Colombia shows a clear negative correlation between polling station size and reported manipulation.

A robust relationship exists: Smaller stations facilitate broker enforcement via collective monitoring, as demonstrated through various identification techniques including regression discontinuity designs.

Why It Matters: This finding highlights how democratic institutions can be undermined by seemingly unrelated features of electoral systems.