In many recent democracies, candidates compete for office using illegal strategies to influence voters. In Hungary and Romania, local actors including mayors and bureaucrats offer access to social policy benefits to voters who offer to support their preferred candidates, and they threaten others with the loss of a range of policy and private benefits for voting the “wrong” way. These quid pro quo exchanges are often called clientelism. How can politicians and their accomplices get away with such illegal campaigning in otherwise democratic, competitive elections? When do they rely on the worst forms of clientelism that involve threatening voters and manipulating public benefits? ‘Conditionality and Coercion: Electoral Clientelism in Eastern Europe’ uses amixed method approach to understand how illegal forms of campaigning, including vote buying and electoral coercion, persist in two democratic countries in the European Union. It argues that we must disaggregate clientelistic strategies based on whether they use public or private resources, and whether they involve positive promises or negative threats and coercion. We document that the type of clientelistic strategies that candidates and brokers use varies systematically across localities based on their underlying social coalitions. We also show that voters assess and sanction different forms of clientelism in different ways. Voters glean information about politicians’ personal characteristics and their policy preferences from the clientelistic strategies these candidates deploy.