Solidarity is a key ingredient to making society work. Yet, recent developments such as the refugee crisis and the declining support for social democratic parties question the degree of solidarity in Western societies. So what could increase solidarity? The national identity argument (NIA) claims that a stronger national identity can foster solidarity. While this claim was proven in some cases, several others challenged it. This paper sets out to put the NIA to a severe empirical test by distinguishing five different forms of national identity: national belonging, national pride, patriotism, national chauvinism, and the normative perception of national boundaries. The data stems from national surveys in Germany, the UK, and the USA linked to the ISSP. The results reveal no clear support for the NIA. Whether national identity fosters solidarity depends on what type of national identity and what country one is looking at.