Once negotiated, multilateral agreements are very powerful. They cover a wider geographic area, giving signatories a greater competitive advantage. All countries also give themselves the status of the most favoured nation – and grant the best conditions of mutual trade and the lowest tariffs. These agreements between three or more countries are the most difficult to negotiate. The larger the number of participants, the more difficult the negotiations. They are, by nature, more complex than bilateral agreements, insofar as each country has its own needs and requirements. The Doha Round would have been the world`s largest trade agreement if the United States and the EU had agreed on a reduction in their agricultural subsidies. As a result of its failure, China has gained ground on the world`s economic front through cost-effective bilateral agreements with countries in Asia, Africa and Latin America. First, the parties that signed a free trade area applicable to trade with non-parties to that free trade area at the time of the creation of that free trade area must not be higher or more restrictive than tariffs and other rules applicable in the same signatory countries prior to the creation of the free trade area. In other words, the creation of a free trade area to give preferential treatment to their members is legitimate under WTO law, but parties to a free trade area are not allowed to treat non-parties less favourably than before the creation of the territory.
A second requirement under Article XXIV is that tariffs and other trade barriers must be eliminated primarily for all trade within the free trade area.  Unlike a customs union, parties to a free trade agreement do not retain common external tariffs, i.e. apply different tariffs and other policies with respect to non-members. This function allows non-parties to free themselves as part of a free trade agreement by entering the market with the lowest external tariffs. Such a risk requires the introduction of rules for determining which products originate may be preferred under a free trade agreement, which is not necessary for the establishment of a customs union.  In principle, there is a minimum processing time leading to a “substantial processing” of the products, so they can be considered original products.