Disclaimer. Don't rely on these old notes in lieu of reading the literature, but they can jog your memory. As a grad student long ago, my peers and I collaborated to write and exchange summaries of political science research. I posted them to a wiki-style website. "Wikisum" is now dead but archived here. I cannot vouch for these notes' accuracy, nor can I even say who wrote them. If you have more recent summaries to add to this collection, send them my way I guess. Sorry for the ads; they cover the costs of keeping this online.
Rustow. 1970. Transitions to democracy: Toward a dynamic model. Comparative Politics 2 (April): 337-363.
Rustow presents a model of democratization based on four stages. (1) National unity--the people must agree that they are a political entity, at least enough that there is no secessionary movement. (2) There must be a family feud--some debate that has the people split into strongly opposing camps. (3) There must be a decision to resolve the debate by means of democratic institutions (even if this decision is only a side effect of the resolution). (4) "Habituation": over time, the people will get used to this pattern and come to value democracy itself.
Rustow is highly critical of Lipset, Almond/Verba, and others who suggest that a consensus on civic culture or a level of economic development (Lipset) are prerequisites. If anything, these are the results of democracy, not its causes.
Przeworski's ideas in "Democracy and the Market" (esp. ch 2) make Rustow look simplistic. The family feud idea isn't problematic (Przeworski takes as his starting point a society with hardliners and reformers in government and moderates and radicals in society, which assumes there is some "family feud" around which they're divided). But Rustow's idea of having a decision to resolve the debate with democratic institutions seems a little simplistic--Przeworski spends a long time in ch 2 explaining why you might get democracy even when some groups (reformers) don't intend it. And the "habituation" idea is also a bit simplistic. Przeworski shows how the different mechanisms of arriving at democracy produce either a more or less stable democracy in the first place. He specifically takes on this idea of "habituation" on page 86 and argues that it is more apparent than real; if the institutions were set up provisionally, habituation won't help much, but if they were set up well, they'll be stable from the start.
Research on similar subjects