Donald Trump’s initiative echoes past mistakes and could provoke adversaries and undermine efforts toward nuclear diplomacy

With a stroke of his pen, Donald Trump last week ordered an “iron dome for America” – an act that risks sparking a destabilising global arms race. Mr Trump’s proposal takes its name from Israel’s air defence system, but it is cast in more ambitious terms for the US: a space-based interception system designed to counter nuclear, hypersonic and cruise missile threats.

It is also the latest turn of the wheel in a cycle of escalation. Moves by Washington to “increase security” have repeatedly ended up making the world more volatile and unsafe. The historic chance to eliminate nuclear weapons in 1986 slipped away over Ronald Reagan’s insistence on America’s unproven “Star Wars” missile defence system. In 2002, George W Bush – citing the threat from North Korea – ditched the anti-ballistic missile treaty, which was built on the idea that mutual vulnerability cools the nuclear arms race while unchecked defences fuel it. In The New Nuclear Age, Ankit Panda points out that Russia and China responded with countermeasures to ensure “their nuclear forces would have the ability to penetrate a sophisticated US system”.