Key points for reflection:

• Sovereign equality requires the consent of States for obligations to be accepted
• Decentralised enforcement has often meant that States take matters into their own hands
• There has been a move throughout history from forcible to strictly non-forcible measures
• Reprisals: originally permissible punitive responses, now effectively obsolete
• Acts of retorsion: perfectly lawful but nevertheless unfriendly responses
• Countermeasures: non-forcible responses that allow for the non-performance of certain legal obligations under limited circumstances
• Sanctions: a term usually reserved for decisions of international organisations