Why do states intervene in elections abroad? This article argues that outsiders intervene when the main domestic contenders for office adopt policy positions that differ from the point of view of the outside power. It refers to the split between the government's and opposition's positions as policy polarization. Polarization between domestic political forces, rather than the degree of unfriendliness of the government in office, attracts two types of interventions: process (for or against democracy) and candidate (for or against the government) interventions. The study uses a novel, original data set to track local contenders’ policy positions. It shows that the new policy polarization measurement outperforms a number of available alternatives when it comes to explaining process and candidate interventions. The authors use this measurement to explain the behavior of the United States as an intervener in elections from 1945 to 2012. The United States is more likely to support the opposition, and the democratic process abroad, if a pro-US opposition is facing an anti-US government. It is more likely to support the government, and undermine the democratic process abroad, if a pro-US government is facing an anti-US opposition. The article also presents the results for all interveners, confirming the results from the US case.