The Syrian crisis illustrates the struggles of international law to cope with injustices and violations of legal norms, including the ban of the prohibition of chemical weapons. The Security Council has been blocked over two years, due to an irresponsible use of prerogatives that are out of time. This has created dilemmas of protection. This article examines claims relating to ‘humanitarian intervention’ raised in the Syrian context. It questions whether greater flexibility towards military strikes or an ‘affirmative defense to Art. 2 (4)’ offers a proper remedy to deal with this dilemma. It argues that a case-by-case logic, with a differentiated matrix of assessment, provides a more promising way forward than claims for new regulation.