China's top-down political system, under pressure from a growing middle class empowered by wealth and social networks, is likely to "blow up at some point," US academic Francis Fukuyama told AFP in an interview.

"China has always been a country with a big information problem where the emperor can't figure out what's going on" at a grassroots level, said Fukuyama, best known for his 1992 book "The End of History and the Last Man," which argues that liberal democracy is the fulcrum of social evolution.

"This is in so many respects exactly the Communist Party's problem. Because they don't have a free media, they don't have local elections, they can't really judge what their people are thinking," he said this week, ahead of a conference on geopolitics in Paris.

An isolated central Chinese leadership compensates by gathering information through polling and eavesdropping on the nation's massively used micro-blogging platforms, especially the Twitter-like Sina Weibo, Fukuyama contends.

But these same networks are fueling "the growth of a national consciousness that did not exist under the controlled media setting of the Communist regime," he said.

"That is one of the reasons I think that China's system is going to blow up as some point."

The US academic, based at Stanford University, pointed to the fallout from a crash of China's showcase high-speed trains in July 2011 that left 40 dead and deeply shocked the the nation.

High-level officials sought to bury parts of the twisted wreckage, presumably to impede a thorough investigation as to what caused the accident, but a tsunami of chatter and photos on Weibo forced the government to backtrack.

A historically strong central state held in check neither by organized religion nor by civil society has helped China's leaders engineer spectacular and sustained growth, Fukuyama argues.

"You have to credit them with an amazing performance over the last 30 years."

But the absence of genuine rule by law and mechanisms for holding those in power accountable also leaves he country vulnerable to what he calls "the bad emperor" problem, he added.

"Up to now, their leadership has been composed of people who lived through the Cultural Revolution, and they do not want to see that repeated. But once they die off there's no guarantee you won't get another Mao," he said.

The recent purging of Communist Party boss Bo Xilai on charges of corruption was driven in part by other leaders' fear of his growing popularity, Fukuyama said.

"One of the reasons they felt they had to get rid of him was that he was a charismatic leader... developing a populist base that could blow up the whole system."

The full transcript of the interview can be found at http://blogs.afp.com/geopolitics.