China is expanding its nuclear arsenal at a pace unseen for decades. America is likely to build up its own nuclear capacity in response, prompting Russia to do the same. India may feel compelled to counterbalance China, and Pakistan to offset India. A more complex arms race than that of the cold war looms.

In other news, all American presidents change scientific priorities and modify budgets to reflect their policy goals. But Donald Trump’s actions are unusual. He and his allies have attempted to upend American science wherever it is conducted. Renewable-energy and vaccine research are notable victims.