WHAT the aged Communist rulers of China should worry about is the downgrading of their government's credit rating by Standard & Poor's, a nonpolitical judgment that the Asian recession has caught up with it.

What does give those rulers the most anxiety appears, however, to be a movement called Falun Gong, or Wheel of Law, which keeps doing its thing despite every effort of Beijing. Its thing is breathing, exercise and meditation. Millions are doing it, many in unison, in China and throughout the world.

Beijing never authorized this. Falun Gong is "an illegal organization." Members insist it is no sect or cult. Above all, it is no political party. It is no threat to anything. Yesterday, it was banned.

Communist China has long-since come to terms with private motive not controlled by the Party so long as it seeks personal material gain. But spiritual well-being? No teaching of Marx or Mao condones that.

Falun Gong was founded in 1992 by a former soldier named Li Hongzhi, who has since relocated to New York. It is a revival of centuries-old qi-gong, which channels vital energies through breathing and yoga-like exercises, mixed with other traditional teachings.

Superstition and undermining social order! shout Communist authorities. Beijing was shocked in April when the movement marshaled 10,000 followers in a quiet demonstration at the leadership compound. A round-up of 70 members this Tuesday provoked protests in some 30 cities.

The Communist Party wants everyone in line by Oct. 1 to commemorate the 50th anniversary of Communist rule over all China. What if millions were not in line but off in parks or homes: breathing, meditating, exercising, renewing physical and spiritual energies?

There is little likelihood the Communist Party and People's Liberation Army can stamp out such a thing. How much smarter it would be to claim that Chairman Mao thought it up.