Oren Dorell

USA TODAY

WASHINGTON — The one country in the world that has the leverage to turn North Korea away from developing nuclear weapons seems unwilling to take that step.

China is North Korea's neighbor, protector, chief trading partner and economic lifeline. And though it condemned North Korea's nuclear weapons test on Friday — and agreed to sanctions in response to a test in January — the Beijing government shows no signs that it will actually crack down on the communist nation.

For the international community to convince North Korean leader Kim Jong Un that nuclear weapons will lead to risk, “he needs to face a risk,” said Scott Snyder, an analyst at the Council on Foreign Relations.

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That risk can only come from its giant neighbor, which views North Korea as a necessary buffer between its border and U.S. ally South Korea, where nearly 30,000 American troops are stationed.

“China does not want to put in motion instability (in North Korea) that would advantage the United States,” Snyder said. “Their first priority is to maintain stability on their border. That means they’re unwilling to put North Korea’s survival at risk.”

North Korea already faces a series of international sanctions, but they lack bite because the country is so isolated from international trade and finance.

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While the U.S. government says sanctions work, a recent analysis by John Park of Harvard University and Jim Walsh of MIT concluded that sanctions imposed by the United Nations Security Council “have not worked, and that in some ways, the sanctions have had the net effect of actually improving (North Korean) procurement capabilities.”

One effect of sanctions is that North Korean trade with nations other than China has come to a virtual halt. But China allows numerous state-run companies from North Korea to operate on its soil and those have learned to adapt, Park and Walsh wrote in their study, “Stopping North Korea, Inc.: Sanctions Effectiveness and Unintended Consequences.”

The North Korean managers in charge of these companies have hired better Chinese middlemen, moved to China to improve their effectiveness and expanded their nuclear procurement operations in Hong Kong, Southeast Asia and North Korean embassies around the world, the study found.

Some analysts, such as Gordon Chang, author of Nuclear Showdown; North Korea Takes on the World, urge the U.S. to impose sanctions on Chinese companies that aid North Korea's nuclear program.

“The most important thing is imposing costs on China,” Chang said. “It would work to our disadvantage, but we have to remember that North Korea is quickly developing a nuclear capability to put nuclear warheads on ballistic missiles that can reach the continental United States.”

Bonnie Glaser of the Center for Strategic and International Studies in Washington, D.C., says part of the problem is that China’s government doesn’t control everything that’s happening on its soil. Corruption is rife, and midlevel and local officials may turn a blind eye or profit from illegal transactions.

“The Chinese don’t see this as a top priority for the United States,” Glaser said. “They will treat the nuclear issue as a top priority when the U.S. does.”

The Chinese acted quickly last year when President Obama sent a message to Chinese President Xi Jinping that computer hacking and intellectual property theft were top issues that threatened the U.S.-China relationship.

“When that message is issued, the Chinese stand up and listen,” she said.

If the Chinese think the U.S. is going to resort to force or adopt a strategy to overthrow North Korea's leader, “the Chinese would react pretty quickly,” Glaser said. “What threatens them is not the nuclear program but the reaction to the nuclear weapons program, particularly from the United States.”