THE queue is perhaps a thousand people long. It snakes around the dusty, rubbish-strewn back lot of a giant supermarket in the heart of Caracas, Venezuela’s capital. The store is the flagship of the government-run Bicentenario chain, part of a project started by President Hugo Chávez, who died in 2013, and continued by his successor, Nicolás Maduro, to seize control of the production, import and distribution of food. Never again, they swore, would opponents of the government be able to limit access to food, as they did during a business-led strike in 2002-03. Instead, it is the regime’s hare-brained policies that are plucking food from citizens’ mouths.

“I came here for milk,” says a young mother from El Valle, a working-class district a few kilometres to the south-west. “In El Valle, there’s nothing.” She is carrying a tiny baby, while her four-year-old daughter helps with the modest purchases she has managed to make. Today the Bicentenario has sugar, maize flour, chicken and toilet paper at giveaway, government-controlled prices—but no milk. It is 9.30am and customers who began queuing at six o’clock are just emerging. Hundreds more wait outside a narrow gate in the 3-metre-high railings around the lot. Uniformed police keep order; most customers seem resigned rather than belligerent.

But the shortages are undermining support for the autocratic regime’s “21st-century socialist” experiment, especially among the poor, its intended beneficiaries. As queues lengthen across the country, there have been protests and some looting and violence. Fights break out, the strong snatch shopping from the weak and shots have reportedly been fired on occasion. Supermarkets have banned customers from photographing empty shelves, presumably under government pressure. Police have arrested journalists and charged them with disturbing the peace as they tried to report on food shortages. Several state governors have forbidden queuing overnight, perhaps sensing that it looks more shameful than when it happens during daylight. Government stores limit customers to shopping one day a week, assigning the day according to the last number of their identity cards.

The government insists it is the victim of “economic warfare” waged by the opposition. According to one official, the children of the rich are “infiltrating people into the queues” to cause trouble. The real source of trouble, private-sector economists agree, is price and exchange controls imposed by the government, along with nationalisations of food processing and farmland. The diving price of oil, virtually Venezuela’s only export, means that the government can no longer import its way out of trouble. Earnings of foreign exchange are expected to drop by $35 billion this year, from $65 billion in 2014.

With opinion polls indicating that more than 80% of Venezuelans blame the president for the situation, the opposition Democratic Unity (MUD) alliance senses an opportunity. Last year its former presidential candidate, Henrique Capriles, opposed street protests led by a rival MUD faction, which left 43 people dead. He argued for waiting until the full effects of the crisis were felt by the poorest communities, where support for the government has been strongest.

On January 14th Mr Capriles called a press conference to say that these differences had been overcome. On January 24th the MUD will stage a mass “empty pots” rally against the government. Divisions within the opposition are one reason why Venezuela’s “Bolivarian” regime has held on to power since 1999. The signs of greater unity suggest that the opposition may begin to pose a more serious challenge, starting with legislative elections this year.