Compared to many of their counterparts in continental Western Europe, the American and Korean labor union movements have proven to be much less committed to the development of solidaristic welfare programs that adequately cater for all wage earners, including the least privileged. According to conventional wisdom, this behavior was primarily the result of their political weakness. This chapter argues that the weak commitment of the American and Korean labor union movements to the development of solidaristic welfare programs cannot be attributed solely to their weak power resources. What also matters is the fact that both union movements were organized in a narrow manner for privileged workers. This illustrates how union membership composition shaped the attitudes of the American and Korean labor movements towards welfare, as well as the welfare outcomes in the two countries.