There are significant differences between unions and free trade zones. Both types of trading blocs have internal agreements that the parties enter into to liberalize and facilitate trade between them. The key difference between unions and free trade zones is their approach to third parties [lack of ambiguity needed]. While a customs union requires all parties to apply and maintain identical external tariffs on trade with non-parties, parties to a free trade area are not subject to such a requirement. Instead, they can set and maintain any customs regime for imports from non-parties, as they see as necessary.  In a free trade area without harmonized external tariffs, the parties will adopt a system of preferential rules of origin to eliminate the risk of trade diversion [necessary ambiguities].  In the first two decades of the agreement, regional trade increased from about $290 billion in 1993 to more than $1 trillion in 2016. Critics are divided on the net impact on the U.S. economy, but some estimates amount to 15,000 net jobs domestic territory because of the $15,000-a-year deal. Bilateral trade agreements aim to expand access between the markets of two countries and increase their economic growth. Standardized business activities in five general areas prevent a country from randomly stealing innovative products in another way, rejecting low-cost goods or using unfair subsidies. Bilateral trade agreements harmonize rules, labour standards and environmental protection. The comparative advantage theory helps explain why protectionism is generally unsuccessful.
Proponents of this analytical approach believe that countries working in international trade have already worked to find partners with comparative advantages. If a country moves away from an international trade agreement, when a government imposes tariffs, etc., it can bring local benefits in the form of new jobs and new industries. However, this is not a long-term solution to a trade problem. One day, this country will be at a disadvantage compared to its neighbours: countries that have already been able to produce these items at a lower opportunity cost. Trade liberalization promotes free trade, which allows countries to trade goods without regulatory barriers or related costs. This reduction in regulation reduces costs for countries that trade with other countries and may ultimately lead to lower consumer prices, as imports are subject to lower costs and competition is likely to intensify. Both the creation of trade and the diversion of trade have a decisive impact on the establishment of a free trade agreement. The creation of trade will result in a shift in consumption from a cost producer to a low-cost producer, which will lead to an expansion of trade. On the other hand, trade diversion will mean that trade will move from a low-cost producer outside the zone to a more expensive producer in the free trade agreement.
 Such offshoring will not benefit consumers under the free trade agreement, which will be deprived of the opportunity to purchase cheaper imported goods. However, economists note that trade diversion does not always harm the overall national well-being: it can even improve national well-being as a whole if the volume of misappropriated trade is low.  The North American Free Trade Agreement (NAFTA) is a pact to remove most of the barriers to trade between the United States, Canada and Mexico that came into force on January 1, 1993. Some of its provisions were implemented immediately, while others were phased in over the next 15 years. These occur when one country imposes trade restrictions and no other country responds. A country can also unilaterally relax trade restrictions, but this rarely happens. This would penalize the