Clientelism is the exchange of goods and services for political support, often involving an implicit or explicit quid-pro-quo. It is a political system at the heart of which is an asymmetric relationship between groups of political actors described as patrons and clients and political parties. The key issue is that instead of focusing on providing collective goods, politicians focus on providing well targeted private goods. Since these private goods can be targeted to subgroups of poor or underprivileged voters, clientelism can often be confused with progressive politics. However, in the long run, they weaken democracy to the extent that political actors (politicians and actors) tend to focus in a private exchange relationship, forgetting about genuine participation and construcion of collective projects. A plausible conjecture then is that societies where clientelism is pervasive tend to see more volatile political parties and policies, because actors do not care about ideologies, they care about the goods being exchanged. Clinetelism is legal, and for some period of time may even be functional or cohesive. However, there is a thin line between clientelism and corruption, the use of office for private gain at the other side of the law. Quite often, a connection between clientelism and coruption is "machine politics," where what is being exchanged is jobs for votes in a hyerarchical way. Political bosses provide jobs for allies in exchange for their support and the support of those appointed or given goods by these lower bosses. At some point in the pyramid, jobs need not even be provided, but just the promise of jobs. Jobs and private goods must be scarce in these societies, otherwise bosses would have no power. Beware: I'm working on this (actually, I've been working on this for the last 30 years, since the times I was a boss of the Catalan Young Socialists myself... but now more than working on it, I'm thinking about it, which is probably more dangerous).