This year, we have grown accustomed to thinking about China's strengths. We have been awed by its mountainous foreign exchange reserves and by its ability to power ahead in a global downturn. We have seen its ever-more sophisticated military and naval hardware on display. And we have witnessed its growing confidence on the world stage, to wit, its shrill lectures on the dangers of the US deficit and a weakening dollar.

But our infatuation with China's strengths is in danger of blinding us to its palpable weaknesses. How else can we explain Beijing's indictment for subversion – after a year being held virtually incommunicado – of Liu Xiaobo, a veteran human rights campaigner?

Mr Liu's “crime” is that he co-authored Charter 08, an appeal for multiparty democracy, constitutional reforms and the rule of law, that was signed by several thousand people last year before it was snuffed from the internet by censors. The Charter, inspired by Czechoslovakia's Charter 77, contained the line: “We should end the practice of treating words as crimes.” Clearly, the Communist party has not heeded that message. The 53-year-old former literature professor, who has already done stints in jail, now faces a further five years, perhaps more, in prison.

The Communist party seems to think that by cracking down hard on Mr Liu, one of the most consistent and high-profile rights activists of the past 20 years, it will scare others into silence. In a depressing recent pattern, China's authorities have, if anything, been clamping down harder on critics even as we fondly imagined that greater wealth would bring greater tolerance. In a year of sensitive anniversaries, including 20 years since Tiananmen and 50 years since the Dalai Lama fled Tibet, censorship of the internet has tightened. Not even mothers campaigning for justice – after their children were crushed by sub-standard buildings in the Sichuan earthquake or poisoned by tainted milk – have been spared routine harassment.

The Communist party's treatment of Mr Liu, a patriot who has chosen to remain in China rather than sneak off into exile, is abhorrent. It should release him immediately and accept that in an increasingly prosperous society of 1.3bn people not everyone will toe the party line. Sadly, there is little chance of that. That it remains so intolerant of dissent does not augur well for China's long-term stability. Until the Communist party works out how to deal with a plurality of views, it will head a state that is brittle, not strong.