This analysis examines the economic impacts of proposed US tariffs under Donald Trump’s candidacy, using a macroeconomic model adapted from Baqaee-Farhi (2024) model. The tariffs would significantly reduce GDP across major economies: -0.64% in the United States, -0.68% in China, and -0.11% in the European Union. The proposed 100% tariff on vehicle imports would severely affect US electric vehicle affordability and adoption, as imported EVs represent approximately 30% of the domestic market, potentially undermining emissions reduction targets. Within Europe, impacts vary considerably, with Germany facing a -0.23% GDP decline while Italy experiences minimal effects (-0.01%). The 10% universal tariff would prove most damaging to European economies overall. Certain sectors, particularly German automobile exports, face disproportionate risks requiring targeted protection. Retaliatory measures by China or the EU would exacerbate negative outcomes and risk triggering a destructive trade war. The analysis specifically cautions against using the EU’s carbon border adjustment mechanism (CBAM) for retaliation, as this would necessitate unrealistically high carbon prices on US import embodied emissions and could undermine CBAM’s broader acceptability among trading partners. The findings emphasize the need for careful policy consideration to avoid mutually damaging escalation.