Аннотация:ABSTRACT The NAIRU (non‐accelerating inflation rate of unemployment) theory has become the mainstream theory in explaining unemployment in Europe and is often used to justify demands for a cutback of the welfare state, such as reducing unemployment benefits. Close inspection reveals that it, perhaps surprisingly, shares some arguments with Post Keynesian and even Marxist theory. The paper proposes an underdetermined, encompassing NAIRU model, which is consistent with several theoretical traditions. Depending on the closure with respect to demand formation and determination of the NAIRU itself, the model allows for New Keynesian, Post Keynesian and Marxist results.