Ursula von der Leyen was preparing to claim a rare victory on Saturday, sealing a trade pact with South America¡¯s biggest economies. U.S. President Donald Trump had other ideas.

Moments before von der Leyen stepped to the podium in Paraguay, Trump dropped a blistering announcement: He was piling more tariffs on Europe over its support for Greenland.

As the European Union¡¯s top executive, von der Leyen was suddenly in an unexpected spotlight as people waited to see if she would publicly rebuke the U.S. president¡¯s latest threat to unravel alliances built over decades.