The aim of this Policy Brief is to define the threat of trade retaliation that would tip the balance of power in favor of the European Union in response to the protectionist agenda of the new US administration, while limiting the focus to trade in goods in order to avoid extending the trade war to services. First, we estimate the export losses incurred by European exporters in a simple scenario of US protectionism: plus 10 percentage points (pp) on US duties on all European products. We then calculate the uniform European customs duty on a list of products that would impose a commensurable loss of exports on American exporters. As the European Union’s strategy is constrained by the interdependence between the economies on both sides of the Atlantic, we first draw up a “negative” list, taking account of trade dependency on imports: Imposing tariffs on these 412 products could call into question the resilience of European value chains. Of the remaining products, we then identify 1,064 product groups for which the European Union accounts for at least 20% of US exports. To inflict on the United States market losses equivalent to those suffered by European exporters would require the application of an additional customs duty of 40 pp to the American products on this “positive” list – which would likely lead to a spiral of trade conflict, and be costly for both parties.