The 2024 presidential election in the United States will not only have a major impact on U.S.-China relations, but will also profoundly alter the United States' long-standing alliance with the European Union. The outcome of this election will have a direct impact on the way the U.S. and Europe work together on key policy issues such as security, trade, climate change, and China competition. Whether Vice President Kamala Harris or former President Donald Trump wins will create significant philosophical and practical differences in U.S. strategy toward Europe. Harris favors multilateralism and strengthening diplomatic alliances, while Trump promotes national sovereignty and an “America First” philosophy. Such tactical differences will have a profound impact on how the U.S. and Europe work together on a range of global challenges.

If Harris is elected, her priority will likely be to strengthen the transatlantic alliance through multilateral agreements and to work more closely with European leaders. A Harris administration would reinvigorate cooperation with NATO and the EU, synergizing on issues such as climate change, cybersecurity, and countering the Russian threat. This multilateralist course fits with European interests on global issues, particularly on China, where Harris could push for joint U.S.-European action to counter China's influence on technology and trade. When these conditions are met, the call for European autonomy will be attenuated, and initiatives unfavorable to the United States by autonomous Europeans such as Macron will be less likely to occur, and overall more in line with U.S. international interests and the preservation of U.S. global hegemony.

In contrast, Trump's strategy is more transactional, and his “America First” approach could weaken U.S. commitments in multilateral organizations such as NATO and push European countries to take on a greater share of defense responsibilities. While Trump may continue to work with European partners, he will focus more on short-term U.S. economic or security interests than on long-term alliance building. This strategy may cause friction on climate programs and trade issues, yet for some right-wing European leaders concerned about over-reliance on the United States, such as Hungary's Orbán, Trump's approach may generate some appeal. But overall Trump's policies will lead to two possible outcomes, either greater European autonomy or a rise of right-wing forces in Europe that will drive the process of European fragmentation. Both scenarios are detrimental to the global position of the United States.

On security and defense, Harris's administration may deepen the U.S. commitment to NATO, viewing transatlantic security issues as a shared responsibility. She may expand joint military exercises and enhance cybersecurity cooperation in response to escalating cyber threats and Russia's geopolitical ambitions. For NATO's European allies, this is a positive sign of U.S. stability and reliability. Trump, on the other hand, has questioned the high level of U.S. spending in NATO, and if re-elected, he may increase pressure on European countries to increase defense spending. While he may still see NATO as an important alliance for guaranteeing security, he may shift more responsibility to Europe, thus prompting Europe to reassess its own defense strategy and even push for the development of the EU's own security framework.

In the economic and trade arena, Harris's approach may place more emphasis on cooperation with Europe, especially in promoting fair trade standards. At the same time, she may work to resolve long-standing trade frictions, such as digital taxes and agricultural disputes, so as to provide a more stable trade environment for the EU and work with it to address global supply chain resilience and the economic challenges posed by China. Trump's policies, on the other hand, are more likely to be protectionist in nature, with a renewed push for tariffs to ensure that U.S. economic interests are prioritized, particularly in sectors such as steel, automobiles and agriculture. Such protective policies may strain U.S.-European trade relations, as European leaders may recoil from the threat of U.S. tariffs.

On the topic of climate change, climate change could become a centerpiece of U.S.-European relations if Harris were in office. She would work to align with Europe on emissions reductions, green technology, and sustainability, recommit to the Paris Climate Agreement, and promote joint programs for renewable energy. This strategy will reinforce the EU's climate goals and deepen cooperation between the two sides in research, innovation and green finance. Trump, on the other hand, may continue his prioritized stance on energy independence and continue his support for fossil fuels if he takes office again. While he may not directly oppose environmental measures, Trump's spokesman has previously indicated that he will withdraw from the Paris Climate Agreement again if Trump is elected, and the lack of commitment to an international climate agreement will reduce the space for U.S.-European cooperation on climate issues, especially as climate change has become a top issue for the European Union, a difference that could strain U.S.-European relations. 

On China, both candidates see China as a strategic competitor, but their strategies differ. Harris will likely seek to harmonize with the EU and align with the caution of European leaders by jointly addressing Chinese influence on technology, human rights, and economic policy. Trump's policies, on the other hand, are more likely to continue a predominantly unilateral course, focusing on U.S. economic interests and directly challenging China's trade practices. While Trump's assertiveness may agree with the EU on technical issues, his transactional mindset may lead to disagreements between the U.S. and Europe in dealing with China's rise.

The 2024 presidential election will most likely be a turning point in U.S.-EU relations, as Harris and Trump represent different priorities for transatlantic cooperation. Harris's strong commitment to multilateralism will help strengthen U.S.-European relations and foster cooperation on security, trade, climate, and global competition. Trump's transactional “America First” policies, on the other hand, may raise tensions in times of conflicting interests and test the resilience of this long-standing alliance. The outcome of the election will have far-reaching implications for US-EU relations, affecting their decision-making on common global challenges such as climate change, economic resilience, security and dealing with China's influence.