The U.S. has put pressure on countries like Iran and North Korea with economic sanctions. For these sanctions to work and produce meaningful negotiations and agreements, other countries have to also agree to and enforce sanctions. China, however, is undercutting U.S. efforts in both Iran and North Korea.

Since President Trump pulled out of the Iran deal, he has moved to reimpose sanctions, and with the goal to “build a global coalition to put pressure on Iran.” Iran isn’t feeling as much pressure as it might, however, as China has continued to strengthen its ties with Tehran.

China has hosted Iranian Foreign Minister Javad Zairf and Chinese President Xi Jinping has visited Iran, and both countries have indicated their willingness to engage in ongoing diplomatic relations. Economically, China has also sought to incorporate Iran into its "Belt and Road Initiative" and has pumped billions of dollars into Iranian infrastructure projects. (The Iranians seem unbothered by China's brutal treatment of its Muslim minority in Xinjiang province.) China has also looked to Iran as a good source of energy, and has moved to purchase more Iranian oil. China has also hosted joint military exercises with Iran in the Persian Gulf.

These efforts undercut the ability of the U.S. to isolate Iran and negotiate a new deal. China’s successful political and economic inroads in Iran also have given China a new foothold in the region and have meant that Chinese companies, rather than American owned enterprises, have been able to move into Iranian markets.

In North Korea, China also complicates U.S. sanctions. Beijing has long exerted influence and engaged with the northern dictatorship since China sent troops during the Korean War. More recently, the ongoing relationship between China and North Korea was indicated by King Jong Un’s choice of his first meeting with a foreign leader – Chinese President Xi Jinping of course. Since then, the two leaders have continued to meet.

Economically, China is North Korea’s biggest trading partner and accounts for about 90 percent of all trade in North Korea. Beijing has also reportedly promised economic support to North Korea – an effort that North Korea likely sees as a way to gain economic reform without having to give up nuclear capabilities as the U.S. has demanded. Moreover, Chinese parts have been found on North Korean rockets indicating that even while Beijing might uphold United Nations sanctions, Chinese goods are still flowing across the border though both legitimate trade and smuggling.

Like Iran, China also has its own interests in North Korea. Primarily, Beijing is concerned with stability and, in particular, the threat of regime collapse. Such collapse would likely trigger a flood of refugees into China that Beijing would be ill prepared to deal with. China also doesn’t want the U.S. to gain power in the region – especially in North Korea, which Beijing regards as a buffer between U.S. troops stationed in South Korea. To this end, China has continued to build its ties with North Korea while also discouraging other countries like the U.S. from pushing Pyongyang too hard out of fear of instability.

As in Iran, China has undercut U.S. negotiations with North Korea. Beijing’s support has likely emboldened Kim Jong Un to make more demands and fewer concessions while not firmly committing to denuclearize. Trump has expressed concern over the role of Beijing in North Korea, tweeting earlier this summer that the world's most populous nation "may be exerting negative pressure on a deal because of our posture on Chinese Trade – Hope Not!”

Although increased animosity towards the U.S. in light of the trade war is certainly part of the reason this is happening, it's really more complicated than that. China also has its own ambitions and agenda for involvement in Iran and North Korea that go beyond U.S. tariffs.

Regardless of Beijing’s reasons, however, China is undercutting the ability of the U.S. to negotiate. That signals not only Beijing’s increased power on the world stage, but also that countries like Iran and North Korea may no longer feel obligated to bow to U.S. demands to build their economies.