Donald Trump's election to a second term as President of the United States could redefine the balance of power between Europe and its traditional ally across the Atlantic. In the face of this political upheaval, European leaders are confronted with critical questions about the future of their security, their strategic autonomy, and their economic partnership with the United States. As Europe is already weakened by internal tensions, Trump's return rekindles fears of an American disengagement in defense matters, as well as the threat of a trade war.