Within hours of the polls closing, Asian stock markets dipped, then recovered. That small wobble captured the dilemma facing investors after the Democrats took both the House of Representatives and the Senate: the result removes a president's unchecked power, but it may also make him less predictable. Markets usually punish uncertainty, yet the first reaction was calmer than many expected. Donald Trump conceded defeat and acknowledged that the Iran war had hurt his party, which traders read as a sign of stability.

At the same time, his promise to become "Mr Veto" suggests that legislative gridlock, rather than cooperation, will define the final two years of his term. Holger Schmieding, chief economist at Berenberg, saw something reassuring in the outcome, arguing that voters had rejected a leader with an authoritarian streak and a taste for crony capitalism. The economic backdrop explains why voters were so angry. Headline inflation has climbed to 3.

7%, diesel prices hit a record in August, and a chaotic tariff policy has squeezed small businesses. The US-Israeli invasion of Iran, and the resulting closure of the Strait of Hormuz, triggered what analysts call the biggest energy price shock of the modern era. On Wednesday, Brent crude fell by as much as 9%, dropping below $100 a barrel for the first time in a month, as investors bet that political pressure might eventually restrain the war. Two risks remain.

Democrats are expected to regulate artificial intelligence and the building of datacentres more tightly, which could slow one of the main engines of stock market growth.