So-called 'Magnitsky laws' in various jurisdictions are turning unilateral sanctions into normalised instruments for the international promotion of the rule of law. However, the considerable regulatory and executive flexibility introduced by these laws is at strain with the fundamental requirements of the rule of law, both domestically and internationally. Despite a growing literature on sanctions, a systematic and comparative assessment of Magnitsky laws against both the national and international requirements of the rule of law is still lacking. This paper offers a first comparative analysis of the compatibility of US, Canadian, UK, and Australian unilateral sanctions laws with the formal and procedural principles of the rule of law that constitute the common core of both its national and international notions. By analysing the formal aspects of the legal basis, design and application of these laws, our study identifies and conceptualises the legislative techniques that enable the normalisation of Magnitsky sanctions. We find that these techniques, which we name the 'generalisation' of sanctions laws, are not inherently incompatible with the rule of law, but so far national legislators have failed to ensure the right balance between the flexibility introduced by such techniques and the rigorous requirements of legality. The principled recommendations we propose based on our findings seek to help lawmakers around the world to strike the right balance between form and flexibility.