This chapter explores the importance of intergroup solidarity in combatting ethnonationalist populism and in sustaining healthy forms of democratic contestation, and the distinctive capacity of trade unions to cultivate intergroup solidarity and elevate it from the workplace level up to the plane of national politics.  That distinctive capacity stems in part from unions’ roots in the experience of shared work and the common interests and intergroup ties that can grow out of that experience, and in part from unions’ ability, and indeed their need, to link intergroup solidarity to economic self-interest.  That is, unions can and must encourage workers to make common cause and to overcome racial and ethnic divisions in order to pursue shared economic interests.