He has toppled Venezuela¡¯s leader, vowed to control its vast oil reserves and threatened other Latin American countries with similar military action. He has talked openly about annexing Greenland, even by force. And, beyond the Western Hemisphere, he has warned Iran that the U.S. could strike it again.

Ushering in the new year with a flurry of aggressive moves and fiery rhetoric just days before the first anniversary of his inauguration, President Donald Trump has taken a wrecking ball to the rules-based global order that the U.S. helped build from the ashes of World War II.

That has left much of the world reeling, with friends and foes alike struggling to adjust to seemingly altered geopolitical realities. Many are uncertain of what Trump will do next and whether the latest changes will be long-lasting or can be undone by a more traditional future U.S. president.