Editor's note: Episode 9 of On China with Kristie Lu Stout focuses on China-North Korea relations -- Wednesday, June 19: 0530 ET, 1230 ET. Watch in Hong Kong at 1730 HKT, 0030 HKT.
Hong Kong (CNN) -- The naughty step is not working.
After the United Nations slapped tougher sanctions on North Korea after its third nuclear test in February this year, Pyongyang screamed in defiance. It canceled its hotline with South Korea, withdrew its workers from the Kaesong industrial complex it jointly operates with Seoul, and carried on with its over-the-top threats.
China may have backed those sanctions but the economic lifeline is still there. Trade goes on between North Korea and China. In 2011, before some of these trade embargoes began, China accounted for an estimated 67.2% of North Korea's exports and 61.6% of imports, according to the CIA World Factbook.
"If you talk to officials at the border, there's no change," says Stephanie Kleine-Ahlbrandt, the North Asian head of the International Crisis Group.
"And a lot of that trade is conducted by government trading companies especially on the North Korean side," adds the Los Angeles Times' Beijing Bureau Chief Barbara Demick. "There's a lot more China could do that it has chosen not to."
So why is China not using its economic leverage to rein in the nuclear threat and proliferator next door?
In a word -- fear.
There's fear of a North Korean collapse that would lead to instability and a refugee crisis along its 1,400 kilometer (880 mile) border with North Korea. And then there's the far greater fear of an all-out conflict that would redraw the geopolitical map.
"Their end goal might be similar in terms of denuclearization, but China is looking at preventing war on the peninsula, which would allow a pro-Western government right on its border," says Kleine-Ahlbrandt.
And there's something else holding Beijing back -- the historic and symbolic relationship with Pyongyang that is hard to give up.
"The Chinese Communist Party thinks of North Korea as this small state that is in its own image," says Demick. "The structure of the North Korean government is very similar to the Chinese government and, in a way, it's the pure Communist state.
"It's just really hard psychologically to dump North Korea."
"They treat North Korea a bit like a wayward child," adds Kleine-Ahlbrandt. " You want to be the one to punish your child, but you're not going to turn them over to police."
But for many people in China, enough is enough.
"Their rhetoric is increasing the number of Chinese who feel very, very disgusted by their behavior, their psyche and their regime," says Zhu Feng, professor of International Relations at Peking University.
"China's government is seriously under fire because I think the majority of Chinese really, really feel that North Korea's bad behavior will inevitably endanger China."
Beijing has mastered the art of "scream-free parenting" with Pyongyang. It has learned to lower its voice and control its emotional reaction with every new threat or missile test.
But public opinion is shifting and China's new leadership is recognizing the need to re-evaluate how it manages its troublesome neighbor.
In a sign of Beijing's evolving approach toward North Korea, Chinese President Xi Jinping recently offered this veiled criticism: "No one should be allowed to throw a region and even the whole world into chaos for selfish gains."
The pressure is on for China to spell out -- and carry out -- the consequences for North Korea's bad behavior.