Free trade is a trade policy that does not restrict imports or exports through legal barriers. In government, free trade is predominantly advocated by political parties that hold economically liberal positions, while economic nationalist political parties generally support protectionism, the opposite of free trade.

Most nations today are members of the World Trade Organization multilateral trade agreements. States can unilaterally reduce regulations and duties on imports and exports, as well as form bilateral and multilateral free trade agreements. Free trade areas between groups of countries, such as the European Economic Area and the Mercosur open markets, establish a free trade zone among members while creating a protectionist barrier between that free trade area and the rest of the world. Most governments still impose some protectionist policies that are intended to support local industry growth and employment, such as applying tariffs to imports or subsidies to exports. Governments may also restrict free trade to limit exports of natural resources. Other barriers that may hinder trade include import quotas, taxes and non-tariff barriers, such as regulatory legislation.

Historically, openness to free trade substantially increased from 1815 to the outbreak of World War I. Trade openness increased again during the 1920s, but collapsed (in particular in Europe and North America) during the Great Depression. Trade openness increased substantially again from the 1950s onwards (albeit with a slowdown during the 1973 oil crisis). Economists and economic historians contend that current levels of trade openness are the highest they have ever been.

Economists are generally supportive of free trade. There is a broad consensus among economists that protectionism has a negative effect on economic growth and economic welfare while free trade and the reduction of trade barriers has a positive effect on economic growthSee P.Krugman, «The Narrow and Broad Arguments for Free Trade», American Economic Review, Papers and Proceedings, 83(3), 1993; and P. Krugman, Peddling Prosperity: Economic Sense and Nonsense in the Age of Diminished Expectations, New York, W.W. Norton & Company, 1994.N. Gregory Mankiw, Economists Actually Agree on This: The Wisdom of Free Trade, New York Times (April 24, 2015): "Economists are famous for disagreeing with one another.... But economists reach near unanimity on some topics, including international trade."William Poole, Free Trade: Why Are Economists and Noneconomists So Far Apart, Federal Reserve Bank of St. Louis Review, September/October 2004, 86(5), pp. 1: "most observers agree that '[t]he consensus among mainstream economists on the desirability of free trade remains almost universal.'" and economic stability. However, in the short run, liberalization of trade can cause unequally distributed losses and the economic dislocation of workers in import-competing sectors.

Features Free trade is characterised by certain principles such as unregulated access to markets and to market information. Taxes, subsidies, regulations, or laws that give some firms, households, or factors of production an advantage over others are often considered to be "trade-distorting" policies that contradict the free trade theory. In a free trade economy, firms cannot distort markets through government-imposed monopoly or oligopoly power. Advocates for free trade strongly encourage pro-free trade trade agreements.

Economics Economic models

Two simple ways to understand the proposed benefits of free trade are through David Ricardo's theory of comparative advantage and by analyzing the impact of a tariff or import quota. An economic analysis using the law of supply and demand and the economic effects of a tax can be used to show the theoretical benefits and disadvantages of free trade.Thom Hartmann, Unequal Protection, Second Edition, Chapter 20. p. 255

Most economists would recommend that even developing nations should set their tariff rates quite low, but the economist Ha-Joon Chang, a proponent of industrial policy, believes higher levels may be justified in developing nations because the productivity gap between them and developed nations today is much higher than what developed nations faced when they were at a similar level of technological development. Underdeveloped nations today, Chang believes, are weak players in a much more competitive system.Pugel (2007), International Economics, pp. 311–312. Counterarguments to Chang's point of view are that the developing countries are able to adopt technologies from abroad whereas developed nations had to create new technologies themselves and that developing countries can sell to export markets far richer than any that existed in the 19th century.

If the chief justification for a tariff is to stimulate infant industries, it must be high enough to allow domestic manufactured goods to compete with imported goods in order to be successful. This theory, known as import substitution industrialization, is largely considered ineffective for currently developing nations.

Tariffs

The chart at the right analyzes the effect of the imposition of an import tariff on some imaginary good. Prior to the tariff, the price of the good in the world market and hence in the domestic market is Pworld. The tariff increases the domestic price to Ptariff. The higher price causes domestic production to increase from QS1 to QS2 and causes domestic consumption to decline from QC1 to QC2.Alan C. Stockman, Introduction to Economics, Second Edition, Chapter 9.N. Gregory Mankiw, Macroeconomics, Fifth Edition, Chapter 7.

This has three effects on societal welfare. Consumers are made worse off because the consumer surplus (green region) becomes smaller. Producers are better off because the producer surplus (yellow region) is made larger. The government also has additional tax revenue (blue region). However, the loss to consumers is greater than the gains by producers and the government. The magnitude of this societal loss is shown by the two pink triangles. Removing the tariff and having free trade would be a net gain for society.

An almost identical analysis of this tariff from the perspective of a net producing country yields parallel results. From that country's perspective, the tariff leaves producers worse off and consumers better off, but the net loss to producers is larger than the benefit to consumers (there is no tax revenue in this case because the country being analyzed is not collecting the tariff). Under similar analysis, export tariffs, import quotas and export quotas all yield nearly identical results.

Sometimes consumers are better off and producers worse off and sometimes consumers are worse off and producers are better off, but the imposition of trade restrictions causes a net loss to society because the losses from trade restrictions are larger than the gains from trade restrictions. Free trade creates winners and losers, but theory and empirical evidence show that the gains from free trade are larger than the losses.

A 2021 study found that across 151 countries over the period 1963–2014, "tariff increases are associated with persistent, economically and statistically significant declines in domestic output and productivity, as well as higher unemployment and inequality, real exchange rate appreciation, and insignificant changes to the trade balance."

Technology and innovation Economic models indicate that free trade leads to greater technology adoption and innovation.

Productivity and welfare A 2023 study in Journal of Political Economy found that reductions in trade costs since 1980 caused increases in agricultural productivity, food consumption and welfare across the world. The welfare gains were particularly large in some developing countries.

Trade diversion According to mainstream economics theory, the selective application of free trade agreements to some countries and tariffs on others can lead to economic inefficiency through the process of trade diversion. It is efficient for a good to be produced by the country which is the lowest cost producer, but this does not always take place if a high cost producer has a free trade agreement while the low cost producer faces a high tariff. Applying free trade to the high cost producer and not the low cost producer as well can lead to trade diversion and a net economic loss. This reason is why many economists place such high importance on negotiations for global tariff reductions, such as the Doha Round.Steven E. Landsburg. Price Theory and Applications, Sixth Edition, Chapter 8.

Opinions

Economist opinions Economists have done extensive work on the theoretical and empirical effects of free trade. Although it creates winners and losers, the broad consensus among economists is that free trade provides a net gain for society. In a 2006 survey of American economists (83 responders), "87.5% agree that the U.S. should eliminate remaining tariffs and other barriers to trade" and "90.1% disagree with the suggestion that the U.S. should restrict employers from outsourcing work to foreign countries". Quoting Harvard economics professor N. Gregory Mankiw, "Few propositions command as much consensus among professional economists as that open world trade increases economic growth and raises living standards". In a survey of leading economists, none disagreed with the notion that "freer trade improves productive efficiency and offers consumers better choices, and in the long run these gains are much larger than any effects on employment".

Paul Krugman stated that free trade is greatly beneficial to the world as a whole, and especially beneficial to people in poorer nations, since it allows them to increase their standards of living. He also stated in 2007 that, as the US trades more with less-industrialized countries whose workers are paid less than equivalent US workers (2007 wages in Mexico were 1/10 what they were in the US, and in China less than 1/20), increased trade with those countries will put downward pressure on unskilled labor rates in the US.

Public opinion An overwhelming number of people internationally – both in developed and developing countries – support trade with other countries, but are more split when it comes to whether or not they believe trade creates jobs, increases wages, and decreases prices. The median belief in advanced economies is that trade increases wages, with 31 percent of people believing it does, compared to 27 percent who believe it does not. In emerging economies, 47 percent of people believe trade increases wages, compared to 20 percent who says it lowers wages. There is a positive relationship of 0.66 between the average GDP growth rate for the years 2014 to 2017 and the percentage of people in a given country that say trade increases wages. Most people, in both advanced and emerging economies, believe that trade increases prices. 35 percent of people in advanced economies and 56 percent in emerging economies believe trade increases prices, and 29 percent and 18 percent, respectively, believe that trade lowers prices. Those with a higher level of education are more likely than those with less education to believe that trade lowers prices.

Research shows that support for trade restrictions is highest among respondents with the lowest levels of education. Hainmueller and Hiscox find: