Aha! Now I understand where the disconnect is, butter. You are equating the act of committing forces with the order to deploy forces. The two are not the same.
Give me a minute to pull up the specific law and I’ll provide a link for you.
In short, the above law provides that the Secretary of Defense (currently Robert Gates) is the one who has the authority to order the assignment of forces to combat (i.e. deployment). He must obtain the approval of the President to ensure that the number of forces he intends to deploy fit within the "force structure" (i.e. number of forces) presribed by the President.
So, while Obama agreed to commit 30,000 additional troops to Afghanistan. He gave no specific order to deploy troops. Secretary Gates ordered the deployment based upon the recommendations submitted to him by the Secretary of the Army (civilian) and the Chief of Staff of the Army (military).
The authority for Gates to give combat deployment orders comes from Obama so it doesn’t even matter who GIVES the orders. What matters is where the AUTHORITY comes from, and the need for actual authorization/authority is what is noted in ii of the elements of lawfulness for Article 90.
Without “the President” authorizing the use of force, neither Gates nor anybody else down the chain of command is authorized to use force. Congress gave the authority specifically to “the President”. Absent “the President” there is no authority to use force. That’s according to Congress (SJ Res 23), who gets ITS authority straight from the Constitution.
And that is understood clearly and acknowledged openly if the location of the deployment is Iran. How is Afghanistan any different?