Thinking deeper, although he is the Vice Chief, the position of the Vice Chief of the country's Court holds no formal status. It is merely a convention for Elder Mr. Liang, whose seniority happens to follow the Grand Secretary, to be the successor if the Grand Secretary steps down, but this is not an absolute certainty.
Minister Wang, with the support of Prince Yu, could leapfrog Elder Mr. Liang to become the Grand Secretary, which is not impossible. And this fellow is more than a decade younger than Elder Mr. Liang.
If Minister Wang indeed ascends, Elder Mr. Liang can forget about becoming Grand Secretary in this lifetime.
Moreover, due to seniority issues, Elder Mr. Liang might be forced to retire early, to save face for everyone.
Ah, this officialdom. Not taking sides is not an option. Just like rowing upstream in a river—falling behind if not advancing.
