IN THE first week of March university students in China will return from a break of six weeks or more. They will find a new chill in the air. While they have been away, officials have been speaking stridently—indeed, in the harshest terms heard in years—about the danger of “harmful Western influences” on campuses, and the need to tighten ideological control over students and academic staff.

Universities have always been worrisome to the Communist Party; they have a long history in China as wellsprings of anti-government unrest. The party appoints university presidents. Its committees on campuses vet the appointment of teaching staff. Students are required to study Marxist theory and socialism. They are not allowed to study politically sensitive topics such as the grievances of Tibetans or the army’s crushing of the student-led protests in Tiananmen Square in 1989.

There is no sign of an anti-party campaign developing on campuses (students are signing up for party membership in droves, believing it to be a path to career success). But since Xi Jinping took over as China’s leader in 2012, the party has been trying to reinforce its control in numerous areas. In the army it appears that Mr Xi has been leading the effort personally (see article). In the academic realm, his involvement in the crackdown now unfolding is less certain. But he has shown no sign of resisting it, and some of the rhetoric warning of the dangers of Western values echoes his own. Mr Xi is certainly no liberal. In his rule he has tightened controls over the media, and there have been numerous arrests and trials of civil-society activists.

That officials have begun to turn their attention to campuses became evident on January 19th, when Xinhua, a state-controlled news agency, published a summary of a document issued secretly by the central authorities in October. It directed universities to “strengthen” their efforts to spread the party’s propaganda and promote its ideology. It told them to educate students better in the history of the party, as well as about the “Chinese dream” (a pet idea of Mr Xi’s). The document also urged educators “firmly to resist infiltration by hostile forces”. It was suffused with the same sense of a party under assault by Western liberal thinking that permeated a secret directive issued in 2013, known as Document Number Nine. That spoke of the threat posed by ideas such as universal values, civil society and press freedom—positive mention of which had occasionally surfaced in some Chinese newspapers and still occurs frequently in university classrooms.

An old-style propaganda campaign is now unfolding. On January 29th Yuan Guiren, the education minister, declared at a conference that “textbooks promoting Western values” would not be allowed in classrooms, nor would “slandering” of the party leadership. Officials at the same meeting echoed his views, including the party chiefs of Peking University and Tsinghua University, the country’s most prestigious colleges. On February 6th a commentary in the People’s Daily, the party’s main mouthpiece, quoted the party chief of Renmin University in Beijing as saying that Marxist thinking must “enter textbooks, enter classrooms and enter brains”.

Unlike Mr Xi’s campaign against corruption, which has been pursued with far greater vigour over a longer period than any other like it in the post-Mao era, the crackdown on campuses may not prove long-lived. Some Chinese academics, though mindful that several scholars have lost their jobs in the past two years because of their liberal views, privately scoff at the ritual repetition of vague slogans that has so far marked the current campaign. Some online commentators have openly criticised it. Ren Zhiqiang, a property developer, wrote to his millions of microblog followers: “Why is it necessary to fear Western values?” He noted that Marx himself was a Westerner.

The education minister and the party leaders of Peking and Tsinghua universities are not known as hardliners. Mr Yuan has spoken positively in the past about Western-style teaching methods which promote critical ways of thinking. One academic at Peking University says “everyone knows” that the three men do not believe their own words about the dangers of Western influences. Few expect the crackdown to affect teaching in such areas as science and medicine which do not touch on politically sensitive issues, even though they rely on Western textbooks.

But the campaign is likely to prompt at least some lecturers to be more cautious. Officials’ ill-defined references to “hostile forces” could be used to target the party’s many critics in university faculties. One newspaper, Liaoning Daily, reported late last year that 80% of students it surveyed in more than 20 universities scattered across five cities had encountered academics who had complained about China or smeared it in class. The “phenomenon of China-bashing”, it said, was “quite serious sometimes”. On February 3rd several official websites published a screed by Zhu Jidong of the Chinese Academy of Social Sciences. It said those who criticised Mr Yuan should be investigated and “a few model examples” of such people should be punished harshly.

Hardliners have long been waiting for an excuse to pounce. In November members of the Chinese Red Culture Institute, a group of scholars and retired senior officials, held a meeting in Beijing at which they complained that Marxism was in retreat and that scholars with Western backgrounds had “sneaked” into academia and government, according to Chinese Social Sciences Today, a journal. “Those who smash the Communist Party’s cooking pot...we will take away their bowls,” participants are said to have vowed.

One university president, Gong Ke of Nankai University in the northern city of Tianjin, has publicly expressed alarm, accusing hardliners of wanting to launch a witch-hunt on campuses such as occurred in the Mao era. His remarks were published on the website of the People’s Daily—a hint that at least some in the party are still in favour of restraint.