China's tough neighborhood has gotten just a little bit tougher for China, diplomatically and militarily, and Beijing ought to blame its own political blundering.
Consider South Korea and Vietnam, two of China's more militarily capable neighbors. During the Vietnam War, South Korean soldiers fought Hanoi's troops. Today, both countries regard that as very ancient history, and they increasingly act as de facto allies. This week, South Korea and Vietnam announced that they will strengthen bilateral defense cooperation and conduct a "strategic dialog" on defense issues. Defense cooperation includes senior officer training exchanges and defense industry collaboration. Shared senior officer training programs are a short policy step away from crafting shared defense plans.
So Vietnam and South Korea see a common interest in blocking China. If Burma (Myanmar) actually flips, it will make it much easier for India to project power into the South China Sea to support Vietnam.
But don't think that these regional developments lift the burden we have of watching China very carefully. Some isolationists like to speak of these developments as if they just happen and as if on their own they protect our interests. That is delusional thinking.
These countries around China's periphery can share worries and cooperate, but in the end they are very isolated from one another and can't apply much military power in support of another country facing Chinese power. China can, using interior lines, defeat them one at a time if they have to.
That's where we come in. Our power can link these separate local points of resistance to Chinese territorial ambitions and give them confidence that they can cooperate with other countries with less risk of being singled out and crushed by Chinese power.