The European social and welfare models are questioned in the context of the internationalization of the economy. The situation is quite different in the US where the combination of a rapid economic growth, full employment and a usually less developed welfare state seem to alleviate economic and social burden of internationalization. A comparative study of the primary distribution of economic revenue between individual's wages, recruitment of new salaries and profits show a convergence between Europe and the US since the eighties. Meanwhile, the design of welfare state continues to oppose the continental euro-model to the US model. Scandinavian and British models maintain also there specificities. But ageing will challenge welfare state in every occidental countries. As a matter of fact it implies an increase of social spending everywhere. So if structural differences are likely to remain between social and welfare models in Europe and with the US one, the regression of public social spending could be stop and a new development of welfare state could appears essential to the equilibrium between market economy exigencies and social needs.