Comrades in Health: U.S. Health Internationalists, Abroad and at HomeSince the early twentieth century, politically engaged and socially committed U. S. health professionals have worked in solidarity with progressive movements around the world. Often with roots in social medicine, political activism, and international socialism, these doctors, nurses, and other health workers became comrades who joined forces with people struggling for social justice, equity, and the right to health. Anne Emanuelle Birn and Theodore M.