The end of 2016 and the beginning of 2017 saw a dramatic change in the global trade picture. Following on the heels of the British referendum supporting the exit of the UK from the EU, the US presidential election resulted in the victory of Donald Trump, who made many protectionist statements during the campaign, in particular threatening China, Mexico, and Germany with import duties. He announced that he would “impose tariffs of 35% on Mexican imports and 45% on Chinese imports to protect American jobs from unfair foreign competition”.
There exists a large economic literature on trade wars. The famous Smoot-Hawley Tariff Act has in particular received extensive attention from economists. In June 1930, eight months after the Wall Street crash of October 1929, the US Congress raised tariffs on 20,000 imported goods. The average tariff on protected imports increased from 39% to 53%. Many US trading partners retaliated against the US in the following months. When global trade collapsed after 1930, the US share in world trade went from 16% to 11% between 1930 and 1935. Irwin (1998) concludes that the Smoot-Hawley Tariff Act led to an efficiency loss in the US Gross National Product of between 0.3% and 1.9%.
Would a new trade war launched by the US government make America lose again? And what could be the economic and trade consequences for US trading partners?
In a recent study we provide an evaluation of potential trade wars launched by the US, with the help of a world model of international trade that looks at 18 scenarios of trade wars (Bouet and Laborde 2017). In these trade wars, we vary the trading partners involved (either China, or Mexico, or both China and Mexico), and also the form that US protection and trade retaliations could take (the US government implements either a 35 percentage point increase on import duties on all imported goods except energy coming from these partners or an approximately 10 percentage point increase on these import duties). We then study different types of trade retaliation implemented by the US trading partner(s) on imports from the US; these result in import duties also varying from about 10% to 35%.
Our first policy conclusion is that there is no scenario under which the US can benefit from either unilateral protectionism applied on these two trading partners or a trade war with these partners. In all scenarios, the impact on US welfare1 or US GDP is either zero or negative. It is true that some US sectors may benefit from these scenarios in terms of value added (textiles, wearing and leather products, electronic equipment, etc.), but this gain would be to the detriment of other sectors (chemical, rubber and plastic products, crops, meat and dairy products, motor vehicles and parts, and transport equipment), as well as to the detriment of workers, both skilled and unskilled, and in both agricultural and non-agricultural activities.
A second policy conclusion comes from the following finding: a 35-percentage point increase of US protection against China and/or Mexico, followed by a similar retaliation, clearly constitutes an overreaction in terms of trade policy. Welfare and GDP losses are significantly larger when the US increase in protectionism and trade retaliation is large (35%) compared to moderate increases (10%).
A third policy conclusion concerns US trading partners. While China is significantly affected by trade wars (in terms of welfare, China experiences losses between -0.2% and -1% in the case of US-China trade wars), the welfare losses for Mexico are potentially huge (between -0.5% and -3.2% for welfare in the case of US-Mexico trade wars, and similar losses for GDP under the same scenario). Furthermore, value added may drastically decrease in some sectors. For example, the Mexican motor vehicles and parts sector and the transport equipment sector currently represent 3.3% of total Mexican value added. In the scenario of a relatively large augmentation of protectionism by the US and a retaliatory response by Mexico, value added in these sectors diminishes by about 22%!
A fourth policy conclusion concerns the emergence of free-riders – that is, countries/regions that benefit from a bilateral or trilateral trade war between the US and its trading partners. This is the case of the Central America Free Trade Agreement (CAFTA) region, which obtains welfare gains ranging from 0.3% to 0.8% under the studied scenarios. This impact is of course associated with increased exports from CAFTA to the US to replace either Mexican or Chinese goods.
Does this study exaggerate the potential magnitude of a trade war? It is true that the recently elected president of the US has made fewer protectionist threats against China and Mexico since he took office compared to the statements made during his presidential campaign. It is also true that even if these threats are executed, we do not have much information about the extent to which trading partners will react (if they will react at all).
Beyond the good markets, China has potentially large retaliatory capacities either through capital and currency markets (for example, through the amount of US dollar and US Treasury bonds detained by the Chinese central bank) or through export restrictions (for example, using its high market share in global production of rare earths). These are clearly strong mechanisms with which the Chinese government can exert pressure on the US government. However, the negative outcomes for unskilled workers in Mexico and the deterioration of the Mexican labour market following an increase in US tariffs will also trigger additional incentives for legal and illegal migration, leading to additional challenges to US-Mexico relations and additional costs for the US.
As a concluding remark, it is important to re-state that trade wars are potentially harmful for the world economy. Protectionism is not the right way to reduce current account deficits, as these are mainly the consequence of insufficient net savings. It is also important to state the importance of the multilateral trade system which provides mediation for the litigation of trade disputes. If the US government believes that some of its trading partners implement unfair trade practices at the expense of US producers, the WTO is the right arena in which to complain and obtain a removal or a change of these practices.
Bouet, A and D Laborde (2017), “US trade wars in the 21st century with emerging countries: Make America and its partners lose again”, IFPRI, Discussion Paper, forthcoming.
Irwin, D (1998), "The Smoot–Hawley Tariff: A quantitative assessment", Review of Economics and Statistics 80(2): 326–34.
 Welfare is defined as the monetary amount that a representative consumer would accept in place of the implementation of a specific protectionist policy.