This paper points to a lost and ignored strand of argument in the writings of liberalism's earliest defenders. These “classical” liberals recognized that market liberty was not always compatible with individual liberty. In particular, they argued that labor markets required intervention and regulation if workers were not to be wholly subjugated to the power of their employers. Functioning capitalist labor markets (along with functioning credit markets) are not “natural” outgrowths of exchange, but achievements hard won in the battle against feudalism. Further, and crucially, the existence of such markets required closing off other market choices.