Secretary of State Rex Tillerson proudly announced on Sunday that the U.S. and China agreed to impose sanctions on North Korea. Wang Yi, the Chinese foreign minister, had a private conversation with his North Korean counterpart in which he warned North Korea not to continue to provoke the international community with missile tests. The agreement between the U.S. and China is being hailed as a diplomatic victory, but it also points to a China that is increasingly assertive and self-assured about its role as a dominant player in the world.

Not even a year ago, China faced huge geopolitical trouble. Several of its neighbors were on the cusp of signing a major free trade agreement helmed by the U.S. The Trans-Pacific Partnership (TPP) would have lowered or eliminated trade barriers among a group of 12 countries and would have brought several countries in the Asia-Pacific region closer to the U.S. by economic necessity. It also pointedly excluded China, so the country would not have benefitted from the transformations the TPP would have wrought on the region. Then Donald Trump was elected president. The TPP is now dead in the water and China is poised to step in to create its own economic alliances in the region through its Asian Infrastructure Investment Bank (AIIB). If the AIIB succeeds where the TPP failed, it could be looked back on as a major turning point for China’s role in the world in the 21^st century.

Less than a year ago, China also had trouble on the high seas. China had been in a number of disputes with its neighbors over artificial islands that it regularly builds in the South China Sea. These islands provide refueling stops and logistics support for Chinese aircraft and ships that patrol the South China Sea. The islands themselves are tiny. However, they do provide China with the means of patrolling the South China Sea indefinitely and allow the Chinese military to inspect its neighbors’ territory with impunity. An ungodly number of countries are entitled to their own stake in the South China Sea by international law, but China is the only country in the region powerful enough to maintain an indefinite watch over the entire sea. That puts its smaller neighbors on edge. Combine this with huge oil reserves under the water, and you’re just asking for a fight to break out.

China had several disputes less than a year ago, but now it seems that momentum is swinging in its favor. The new Filipino president, Rodrigo Duterte, has dropped the demand that China retreat from the South China Sea. The fact that the Philippines is hosting the annual meeting for the Association of Southeast Asian Nations (ASEAN) is telling. A year ago, almost every member of ASEAN had a problem with China in its waters; now, the organization’s very own host is backing down from these complaints. It signals that events are turning in China’s favor.

Tillerson’s collaboration with China is significant, since it is clear that the U.S. alone cannot move on the issue of North Korea. North Korea’s missile tests are an even greater dangerous uncertainty than Donald Trump’s Twitter account and no country in the world wants to deal with its continued belligerence. However, this episode, along with all the other events moving in China’s favor, indicate China’s growing weight on the world stage. Much of what is happening now is setting the world stage for a new era of world politics, one in which China is the main stakeholder in the conflicts to come.