Who are the actual commander-in-chief of US armed force?

This question is inspired by the post of 补贴一下农夫的提议 由 dividend_growth 于 2013-11-01 11:01:11
where Dividend_growth pointed out the importance of military power. 

Who can list a small group of people that are really the commander-in-chief of US armed force?  That is, if the majority of this group want the US armed force to do something, they have the power to have the bills passed in the congress and signed by the president, translating their will into US armed force’s action.

On paper, the president is the commander-in-chief. However, the president (even with the full support from all his cabinet) would not be able to have the armed force to do anything that the president wants, without the support from the congress.  If we take all in, it is too big a group of people (>500).  To make it meaningful, I would think there is a limited number of people (I guess <20), as a group, own the power to have the armed force to do what the majority (probably not a simple 51/49 majority, but more significantly like 75% over 25%) of this group wants. 

Let’s take a moment away to look at this small group of people as commander-in-chief of Chinese Armed force after 1949.  From 1949-1978, I would guess members of the Central Politburo Standing Committee of the Communist Party of China, Ten 1955 army Marshals who were active, plus 2-3 people (on a case-by-case bases) important for a particular issue which call for military action, forms this small group.  Mao, himself, probably owned 30-40% “voting powering” of this “group”, meaning Mao pretty much had the power to have the army to do whatever he wanted unless all other members in this group were fighting against him.  From 1978-1997, I would guess that members of the Central Politburo Standing Committee, the 1955 Marshals who were still (politically) alive, the 8 elders (Deng, Chen, Li, Yang, Wang, Peng, Bo, Deng as Zhou’s wife), plus 2-3 people (on a case-by-case bases) important for a particular issue which call for military action, forms this small group.  Deng, himself, probably owned 15-30% “voting powering” of this “group”, meaning Deng usually need to gain support from the also powerful Chen to ensure a significant majority before he was comfortable to give order to the army.  After 1997 (maybe 1996, or a couple of years before Deng’s death), my guess is that members of the Central Politburo Standing Committee, Politburo committee members from the armed force (who are usually senior member of the Central Military Commission), plus 2-3 people (on a case-by-case bases) important for a particular issue which call for military action, forms this small group for the period.  Nobody owned >10% of “voting powering” of this “group” after Deng.