Economic conditions -- Social conditions -- Politics and government -- 8 Foreign relations -- 3 Relations -- 2 Social indicators -- 2 Social prediction -- 2 more ... 21st century 1 Case studies 1 Case studies -- 1 Civilization -- 1 Congresses 1 Congresses -- 1 Economic conditions 1 Economic policy 1 Equality -- 1 Forecasts 1 Income distribution -- 1 Military policy -- 1 National characteristics, American 1 National security -- 1 Public opinion -- 1 Social aspects -- 1 Social conditions 1 Social policy 1 Social sciences -- 1 Study and teaching (Higher) -- 1 Twentieth century -- 1 less ...