A growing number of countries, including American allies, are striking trade deals as the Trump administration erects a higher fence around its global commerce.

Jake Sullivan, the national security adviser, said in an interview that “we’ve just stuck with our theory, which is managed competition.” Trump and Xi Jinping might have other plans.

Experts said they were “blind” to the Indian Ocean tsunami in 2004. Twenty years later, working toward a world without tsunami deaths is a challenge.