However, large numbers of the new middle classes are economically vulnerable and lack the human capital necessary to keep ascending in the social ladder. Their expectations of higher income and more economic stability often have gone ahead of their actual conditions.
At the same time, political trends and practices have experienced major changes. In half of the Latin American countries the incumbent presidents come from leftist parties that either did not exist or were marginalized only a couple of decades ago. In most countries, political competition has become fiercer and affiliation to political parties has become more fragile and temporary. The renovation of political leadership, which used to depend on family dynasties and patrimonialistic hegemonies, has sped up.
The clientelistic vote has hardly disappeared but it has become more difficult to mobilize, and new non-institutionalized channels of expression of the electorate have gained traction, from street mobilization to Internet social networking. All these changes amount to a political revolution that is contributing to feed expectations of further economic and social progress.
The new demands of the ascending middle classes include not just stable and well paid employment , but also better housing, public services and security, access to social security  and better tertiary education. Since political demands respond more to expectations than objective indicators, more often than never such demands are higher in the cities  and countries that enjoy better living conditions and where progress has been faster.
In the next few years, the revolution of expectations will give rise to strong political tensions and even open social conflict, as already evident in some countries. As usual, the ideological pendulum will lead to demands for renovation of the political power and for reorientation of economic and social strategies.
But the international context will make it harder to meet those demands, especially in countries that depend on natural resource exports  which did not take advantage of the good times to widen economic opportunities and improve the human capital of the new generations.
*Eduardo Lora was a member of the Latin American Development Series  Advisory Committee on behalf of the Inter-American Development Bank  between 2003 and 2012 and co-editor of four books of the Series .