The potential for miscalculation is large and growing. American troops are within miles of Iranian-backed forces in Iraq and Syria. Its warships are nose to nose with Iranian patrols in the Gulf. America recently declared the Guards a terrorist group; then Iran did the same to American forces in the Middle East. Officials on both sides say their intent is peaceful, but who can believe them? America’s accusations that Iran has been planning to attack American forces or its allies in the Middle East are suspiciously unspecific. Violence by Iran’s proxies may be just the sort of provocation that leads America to launch a military strike. Mr Pompeo once suggested that he preferred American sorties to nuclear talks with Iran. Mr Bolton penned an article in 2015 in the New York Times entitled “To Stop Iran’s Bomb, Bomb Iran”. Now even Mr Rouhani appears to agree that the way forward lies with provocation and escalation.
A nuclear Iran would spur proliferation across the Middle East. Bombing would not destroy Iranian nuclear know-how, but it would drive the programme underground, making it impossible to monitor and thus all the more dangerous. The only permanent solution is renewed negotiation. Mr Trump, a harsh critic of America’s foreign wars, therefore needs to keep the likes of Mr Bolton in check. He will face pressure from hardline politicians at home and opposition in the region, not least from Israel.