Eben Moglen is a professor at Columbia Law School and the founder of the software-freedom-law-center (SFLC), established in 2005. He served for many years as the general counsel of the free-software-foundation, working closely with stallman on GPL enforcement and the drafting of gpl-v3.
Moglen brought legal rigor to the copyleft framework that stallman had conceived as a philosophical and political project. His scholarship on intellectual property law grounded the gpl-copyleft-mechanism in mainstream legal theory, helping courts and practitioners understand its enforceability.
His work on gpl-v3 addressed the problems of tivoization and digital-restrictions-management that Stallman identified. He led the gplv3-drafting-process as primary legal drafter. The SFLC pursued GPL enforcement actions — including the landmark busybox-monsoon-multimedia-2007 case, the first US GPL enforcement lawsuit — that gave practical teeth to the four-freedoms.
Moglen's relationship with Stallman was foundational to the institutionalization of the gnu-project's legal framework. He has been a consistent voice for software-freedom-vs-open-source positions aligned with Stallman's rather than with the pragmatic framing of eric-raymond or the open-source-initiative.
bradley-kuhn, who later led the software-freedom-conservancy, worked with Moglen at the SFLC before founding that separate enforcement organization.