US Is Worried China May Make Big Move for Russia
It "would transform the nature of the conflict, turning it into an epochal struggle involving all three of the world's largest superpowers and their partners on opposing sides: Russia, China, Iran, and North Korea aligned against the United States, Ukraine, and their European and Asian allies and partners, including Japan and South Korea."


That presupposes that NATO would go to war for a non-NATO country. There's no national interest.