A recent Commerce Department export control directive required Anthropic to obtain a license before exporting its Claude Mythos 5 and Fable 5 models to any foreign person, whether inside or outside the United States. Because Anthropic could not verify each user's nationality in real time, it disabled the models for all customers worldwide. The Lawfare analysis notes that the legal basis for treating hosted access as an export is questionable, but the government's leverage came from Anthropic's continued control over user access to its models.
Open-weight models present a different problem. Once weights are published and copied, the original developer loses effective control, and no export control directive can recall the copies. Many leading open-weight developers are based in China, where the U.S. government has little practical ability to prevent publication. Proposals to "ban" Chinese models, the article argues, are mostly restrictions on Americans who transact with, host, or integrate those models, not actual bans on publication abroad.
The analysis concludes that broad restrictions on the publication, download, or local use of general-purpose weights would face substantial legal and practical obstacles. Still, the government retains leverage both upstream and downstream of publication, particularly over the supply of computing power used to develop models and the services that help users run or customize them. The article urges applying a marginal-risk framework to decide what a control would actually deny an adversary before using these authorities.