Edward Glaeser argues urbanization is a catalyst for democracy:
Revolution of urban rebels, by Edward L. Glaeser, Commentary, Boston Globe: The Fourth of July is an opportunity to reflect on the long, difficult path to liberty. The organized uprisings, like the American Revolution, that toppled tyrants were often urban affairs that started with surreptitious meetings in crowded pubs and guildhalls. They were led by creatures of the city: merchants, lawyers, weavers, butchers, and brewers. As we celebrate our freedom at spacious suburban barbecues, we should remember that the road to freedom started on far more crowded city streets.
In the fight for freedom between dictatorship and democracy, dictatorship starts with a big edge.
Dictatorships have a small number of insiders who have strong incentives to fight for their regime. Because the benefits of democracy are so widely shared, no one has particularly strong incentives to fight to create or preserve representative government.
Democracies have a massive free-rider problem where all of us have a natural tendency to let someone else die for our liberty. Solving this free rider problem requires coordination and this is what urban density has done for millennia. Urban density connects citizens and enables them to meet and plan and talk. With enough talking, groups like the Sons of Liberty may even convince themselves that it is worth dying for a common cause. Monarchies flourished in our agricultural past, because effective democratic opposition was far more difficult to organize in a dispersed rural setting. ...
Our revolution had its origins in the urban connections between John Hancock, the two Adams cousins, and assorted other enemies of British colonial policy. Brought together by Boston, a merchant-prince could help finance riots led by a brewer. The lawyers could argue cases and the writers could push pamphlets. David Hackett Fischer's account of Paul Revere taught us that this silversmith was not a lone rider, but part of a dense, urban network that collectively fought for independence. The most important urban interactions of all may have occurred in the Second Continental Congress in the days before July 4, 1776. By connecting in a city, the founding fathers hung together instead of hanging separately.
Across countries today, there is a robust correlation between urbanization and democracy. This correlation reflects many things, such as the tendency of more urban places to be richer and better educated, but it also surely reflects the role that cities play in supporting the coordinated action that creates and defends democracies. So enjoy your Fourth of July with as much greenery as you like, but also remember that city air made you free.