The post-Cold War order is ending and the world is rebalancing.

The U.S. reassessment of its commitment to Ukraine and the prospect of a transformed relationship with Russia are prompting governments around the world to similarly rethink their defense and security policies. Europe is pacing this adjustment, but Asian governments will have to shift as well.

Concerns about Donald Trump’s foreign policy crystallized last week during a stunning Oval Office meeting with Ukrainian President Volodymyr Zelenskyy. The ambush by the so-called leader of the free world and his vice president of a man who is leading efforts to repel a bloody invasion made plain that old certainties have evaporated and ties that once bound Washington to partners and allies in Europe have dissipated.