In the new era, European leaders are not only promising to take more responsibility for the conventional defense of their continent; they’re also beginning to talk about an expanded nuclear deterrent of their own. Practically, this would mean leveraging the capabilities of Britain and France, currently the only two European states with nuclear weapons.

For now, Kristersson said, “the American nuclear umbrella is absolutely dominant.” And he has seen no indication that Washington intends to curtail it, even as the Trump administration presses European countries to assume greater responsibility for their own defense. Still, the prime minister said, “it’s a good thing” that there are European countries with such capabilities