What matters today is not whether the Great Wall kept the barbarians out. In fact it did not; eventually they entered in China, triumphant. But the Wall was built, and much remains today stretching across both time and space.It was built at huge cost in lives and time and material— it showed what Imperial power could do when mobilized. It showed the might of Chinese civilization. It was and is a symbol of the importance and grandeur of thousands of years of Chinese state dominance.

So too the Great Fire Wall.

It matters little whether a Virtual Private Network works five hours a day or only five minutes every hour. What matters is that it is necessary at all; what matters is that it is not allowed to work 24 hours a day seven days a week. What matters is that Beijing has a heavy finger on the switch and that that finger, and its power, is visible to all.

During the Cultural Revolution, China descended into chaos as the Red Guard “linked up”—大串联 / dà chuàn lián—using big character wall posters, to spread information and the vast rail links across the country to spread themselves and their ideas.

During the student-led protests of 1989, “linking up” through posters and rail links and roads brought millions to the streets.

Today, the digital equivalent of a poster is an electronic posting. The digital equivalent of a rail line is a fibre optic cable. The spectre of a digital “linking up” is a nightmare to government lovers of order, control and stability.

And so the linking up is blocked.

There is no need to shut the rail lines down; all you need to do is have police in the stations checking ids and guards on the train arresting suspicious groups. There is no need to shut down the Internet. All you have to do is show you can arrest commentators who “forget” to show deference. All you have to do is block foreign services that serve as transmitters and broadcasters of unwanted messages. All you have to do is show that you are monitoring bit by bit, byte by byte and have the power to crack down.

What President Xi Jinping is showing is that to him the only ideology that matters in China today is an ideology of power and not an ideology of ideas. That can certainly be effective for a time, but the use of that power carries a price as well. The current frustrations and anger at Internet access and VPN impotence are just some examples of the costs that may one day become due.