THESE days even seasoned China-watchers are having trouble knowing what is going on. But it is clear that political tensions are high in Beijing following the dismissal of the Communist Party chief of Chongqing, Bo Xilai, on March 15th. Mr Bo's opponents appear to be tightening the noose around him. At the same time, a sudden clampdown on internet gossip suggests the authorities fear that the party's internal battles could trigger wider unrest.

Since the Tiananmen Square protests of 1989, China's leaders have elevated unity over all else. In the build-up to those protests, open evidence of splits in the leadership emboldened reform-minded intellectuals and students to step up demands for political change. As the party prepares for a shuffle of its top leaders later this year, struggles for power might prove destabilising. The authorities' nervous response to the Arab spring last year, with big police deployments in city centres, gave a clue to their unease.

On March 31st, several days after wild and implausible rumours on the internet that powerful supporters of Mr Bo had attempted a coup in Beijing, the authorities began flexing their muscles. They ordered the two most popular microblog services, operated by Sina and Tencent, to impose a three-day ban on one of their most popular user functions—the ability to comment on others' posts. (Each service has more than 300m registered users.) And they arrested six microbloggers, some prominent, for spreading rumours. These included military vehicles in the capital on the night of March 19th.

It is hardly surprising that many Chinese turn to unverified internet sources for news about the leadership's feuding. Since Mr Bo's dismissal, the authorities have uttered not a peep about the reasons for it. Neither have they said why Mr Bo's one-time right-hand man, Wang Lijun, fled to an American consulate on February 6th. Mr Wang is presumably under arrest. Mr Bo may be under some form of detention, too, though for the moment he remains in the ruling Politburo. Nor have officials said anything about the death in November in a Chongqing hotel room of a British businessman, Neil Heywood, who reportedly was sometimes a fixer for the Bo family. There are rumours of a falling-out with the Bos and of a suspicious death.

Mr Bo had been a contender to rise later this year to the Politburo's Standing Committee, the nine people at the very top. His family connections as the son of a revolutionary leader were once an asset. Several other “princelings” like him look set to assume high positions in the autumn—these include Xi Jinping, a blue blood all but certain to be made party head.

For now Mr Bo's supporters appear in retreat. The latest indication of this are media reports of the detention on suspicion of economic crimes of Xu Ming, the wealthy chairman of Dalian Shide Group, a chemical firm. As leader of Dalian, a city in the north-east, in the 1990s Mr Bo was close to Mr Xu. Chinese authorities often attack political figures by dismantling their patronage networks (see next story).

Yet some of Mr Bo's cheerleaders are as feisty as ever. Mr Bo is a champion of those on the ideological left who would like to see the state take on a bigger role, in everything from industry to the provision of welfare. Fan Jinggang, who runs a left-wing website and bookshop in Beijing, both named Utopia, is one of them. He describes what he insists is a conspiracy by America, the World Bank, think-tanks in the West and “traitors” at home, all intent on crushing Mr Bo and the “Chongqing model” which sets store by big spending on welfare projects and the nurturing of state-owned firms.

Mr Bo's supporters are particularly critical of the World Bank and a report it co-published in late February with a state think-tank. The report's proposals for liberalising finance and scaling back state-owned enterprises “harboured evil intentions”, says Mr Fan. His views, though not widely shared by members of China's new middle class, represent a strand of thinking in Chinese politics that connects an array of forces, from born-again Maoists to ultranationalists and hardline elements of the establishment itself.

The internet crackdown may be a sign that China's leaders are closing ranks again. Neither hardliners nor reformists want trouble on the streets. When ethnic unrest gripped the remote north-western region of Xinjiang in 2009, the government shut off access to the entire internet across Xinjiang. It has now issued a warning to China's enthusiastic microbloggers that it might not scruple to do the same to their forums as well.