analyzed by Chinese leadership and think tanks. And I would guess the analysis leads to "non-action" is the optimal action.
South China Sea is not an issue. Vietname is not an issue. They are like hyped stock prices that are filled with bubbles and speculations. They will popped sooner or later.
The biggest issue with China is still internal: how to maintain the course of industrial and urban transformation; how to establish "effective" social institutions such as social security agency, environment control agency, food and drug admin agency, etc. These are the real issues that need 100% attention from Chinese leadership. And issues like Vietname and South China Sea are "artificial" issues that are "staged" by some entities to distract China or push China's hand.
So "non-action" is actually the best action at this moment in time, recognizing the fundamental understanding that South China Sea will always be there and Vietnam is a political issue and not not a military issue.