Administering Space Forces. They're *probably* not line commanders in most cases, otherwise, we likely would have seen them, but instead are most likely staff officers.
There's probably one running the Academy, another one in charge of doctrine (could be the same officer), one for procurement of advanced technologies, etc.
All of this is supposition. I do believe that Blair is promoted to a Brigadier in one of the WC4 endings, but I forget which one and the duties to which he is assigned.
Psych or Bandit Loaf might know more.