The United States and China, along with most other nations, agree the Korean peninsula should be rid of its nuclear weaponry.

But the two global superpowers – one the world’s leading free democracy and Pyongyang’s greatest adversary, the other the largest communist power and North Korea’s greatest ally – differ greatly on their approach to the issue.

This week’s UN Security Council resolution to impose even harsher sanctions on North Korea in response to the regime’s sixth nuclear test reflected the two nations’ consensus on achieving a common goal as well as the differences in their approaches to dealing with the biggest nuclear threat since the Cuban Missile Crisis in 1962.

What would China do if North Korea and the United States go to war?

US President Donald Trump has said several times that China could “easily” help stop North Korea’s nuclear advancement if Beijing agreed to use its economic leverage as North Korea’s top trading partner. However, Beijing has dismissed the argument, saying it is not Beijing but Washington and Pyongyang that should solve their differences.

What Washington wants is an all-out effort to force the reclusive regime to its knees, while Beijing desires mutual compromise to defuse tensions and a return to the negotiation table.

Under the “dual suspension” formula, Beijing has called for the US and South Korea to stop provocative military exercises in exchange for the North freezing its nuclear and missile tests. But the US does not believe such compromises will win corresponding concessions from the Stalinist regime, as the North’s leader Kim Jong-un has a poor record of honouring promises.

While the latest round of sanctions are considered the most extensive to date, they are still a watered-down version of the initial draft resolution. This was a result of a trade-off between two rival UN groupings, with most nations backing the US on one side, and then Russia and China on the other.

North Korea vows to accelerate weapons programme after ‘evil’ sanctions imposed by United Nations

Most analysts believe the sanctions will not be adequate to prevent further North Korean adventurism, as they stop short of a full-blown oil embargo on Pyongyang and blacklisting the North Korean dictator, among other concessions.

Meanwhile, the bigger question hanging over this compromised resolution is whether Beijing will honour the sanctions. Suspicion over China’s sincerity in implementation became clear when the Trump administration threatened to punish Chinese entities who violated the UN pact.

A total oil embargo on North Korea would only lead to war, as it did with imperial Japan

The latest UN resolution amounted to yet another incremental increase of pressure on North Korea. It is the ninth resolution unanimously adopted by the 15-member council since 2006 over the country’s nuclear ambitions. All previous sanctions failed to rein in the regime, instead triggering further escalation and provocation from Pyongyang.

As the North’s weapons tests have continued, the country has claimed it is edging closer to its goal of building a nuclear-tipped missile capable of hitting the US mainland. Trump has vowed to thwart this goal by all means possible. Beijing’s bottom line is the survival of one of its few remaining communist allies, which serves as a buffer zone against any US plans for the containment of China.

North Korea emerges as one of the world’s biggest illicit exporters of small arms, alongside Saudi Arabia and Iran

The world might have to live with the nuclear threat as long as the big powers fail to agree on how to deal with a tiny but rogue state.

Since the end of the second world war, North Korea has been a major sticking point in US-China relations. Kim Il-sung’s invasion of South Korea in 1950 helped turn the US and China into enemies during the early years of the cold war.

Now his grandson, the young Kim, continues to exploit the mistrust between the world’s biggest powers and thus dictates the course of the most important bilateral relationship in global diplomacy.

Cary Huang, a senior writer with the South China Morning Post, has been a China affairs columnist since the 1990s