Donald Trump’s first foreign visit can be considered as a moment to finally provide some conceptual insight into his external policy. It has been wrapped as “principled realism”. So far, it seems to generate additional uncertainty, rather than make things more clear, especially in what oncerns the future of the transatlantic strategic partnership. Undermining mutual longterm commitments is always easier, while an alternative agenda would require additional efforts. It looks like the American-European relations are heading into a crisis, marked by a lack of trust and growing strategic differences over issues that for decades used to be on a joint agenda. This article provides an assessment of how American foreign policy based on “principled realism” can affect transatlantic ties.