Law and legislation 22 Research 8 Taxation 8 Vietnam War, 1961-1975 8 Diplomatic relations 7 Foreign relations 7 Relations extérieures 7 Máis ... Guerre du Viêt-nam, 1961-1975 6 Local transit 6 Transports publics 6 Activités subversives 5 Merchant marine 5 Pollution 5 Subversive activities 5 Impeachment 4 Impeachments 4 Income tax 4 Politique gouvernementale 4 Recherche 4 Small business 4 Transportation 4 Affaire Watergate, 1972-1974 3 Appropriations and expenditures 3 Aspect économique 3 Census 3 Communism 3 Economic aspects 3 Expenditures, Public 3 Énergie nucléaire 3 Foreign income 3 menos ...