This week our cover considers the outlook for the world economy. Turmoil in financial markets and growing evidence of stress elsewhere are, you might think, just the normal signs of a bear market and a coming recession. But, as our special report this week lays out, they also mark the painful emergence of a new regime in the world economy—a shift that may be as consequential as the rise of Keynesianism after the second world war, and the pivot to free markets and globalisation in the 1990s. The era of economic placidity in the 2010s is over.

The immediate fear is of a blow-up, as a financial system that has become habituated to low rates wakes up to the soaring cost of borrowing. But look further ahead and the fundamental trends in the 2020s and 2030s are for bigger government (as spending rises on health care, defence and energy infrastructure) with still-low real interest rates (as ageing populations in rich countries accumulate excess savings). That poses an acute dilemma for central banks. Should they ditch their 2% inflation targets and raise them to, say, 4%? A brave new world of somewhat higher government spending, and somewhat higher inflation, would present both opportunities and dangers. It is time to start weighing them, and their implications for citizens and businesses.

In the first round of Brazil’s presidential election Jair Bolsonaro, the populist incumbent, did better than expected. He had been trailing Luiz Inácio Lula da Silva, a leftist ex-president, by double digits in the polls for months, but on the night he was only five points behind. The two candidates now head to a run-off on October 30th. Mr Bolsonaro, a fan of Donald Trump, falsely suggests that the election is likely to be rigged, and may not accept the result if he loses.

Elon Musk changed course and offered to go ahead with his $44bn deal to buy Twitter, but only if a forthcoming trial that could force him to complete the takeover is stopped. A recent preliminary hearing in the case did not go well for his legal team. The mercurial Mr Musk offered to take Twitter private in April, said the offer was on hold in May, and abandoned the deal in July, prompting the legal action. He has suggested that he will turn the platform into “X”, an everything app, similar perhaps to the superapps that combine messaging, shopping and services in Asia.