Interns are typically not fully licensed to practice medicine without supervision, which is the point of a residency program (they take more exams to this effec

Interns are typically not fully licensed to practice medicine without supervision, which is the point of a residency program (they take more exams to this effect at the end of the residency). This is why the hospital has enormous bargaining power over them and the hours/wages are markedly different from those of attendings. Unionization of residents is still very rare because the hospital essentially has the power to end the residents' careers for such behavior.