Regional trade agreements may pose a threat to the multilateral trading system for the following reasons: 

 The negotiations frequently detract from WTO negotiations in Geneva Most countries benefit from a strong dispute settlement system that develops uniform interpretations of trade rules rather than regional dispute settlement mechanisms which may conflict with global rules. 

RTAs give major trading nations such as the US, China and the EU the power to impose their objectives on the weaker nations who participate in the negotiations Some small countries are not desired as RTA partners,

meaning that without the WTO they have no voice in improving trade terms to their benefit

All of the above