The welfare state is the distinctive contribution of Europe to the modern world. Other places do market capitalism better, and democracy, art and culture at least as well. However, the future of the European welfare state is in question, as a result of economic globalisation, pressures from population ageing and other social changes and the dominance of an EU primarily committed to creating an open market to rival that of the US. An important recent critique of the welfare state project argues that social cohesion and diversity are simply incompatible – with the implication, that as Europe grows more diverse, welfare states will wither. An influential variant of this argument uses statistical modelling to support the argument that greater ethnic diversity accounts for the failure of the US to develop political support for a welfare state on European lines (and implies that Europe's future is American). This article demonstrates that the model used fails to take into account the significance of left politics in European countries. The evidence is that the left substantially counteracts the impact of greater diversity on welfare states in Europe. The case that increased migration will undermine popular commitment to social spending is not proven.