In particular, it authorizes him to "use the Armed Forces of the United States as he determines to be necessary and appropriate". Another word for this is "war". "War" will certainly be the result if he takes advantage of this authorization. (Don't believe me? Just ask the Iraqi army in a week or three.)
You're complaining, I guess, that in this case they authorized him to wage war to (among other things) enforce UN mandates, as opposed to some other reason like revenge or to kill everybody whose name starts with the letter H or to make sure the opium trade lines stay open. Yup, that was a prominent listed purpose in authorizing him to wage war: to enforce some UN mandates. You don't like that. You wish they gave other reasons for authorizing war.
But nevertheless, whether you approve of their reasons and purposes or not, they effectively declared war against Iraq. Declaring war is what they did. And that is what the Constitution says they can do. (The Constitution doesn't, I might add, say that they can't declare war for reasons or purposes which William Terrell or Dr. Frank may find distasteful.)
As far as I understand, the federal constituion doesn't give Congress the power to order an enforcement of a foreign mandate.
I see no reason why Congress can't decide to enforce a foreign mandate, of its own volition, as long as it doesn't conflict with the US Constitution of course. (Which it does not, because the Constitution explicitly grants Congress the authority to declare war, as I feel like I've said a dozen times now.)
If this order is constitutional, through a treaty for instance, then if the UN security council votes down war, the Congress must withdraw its authorization and the president must withdraw the troops.
So you're saying that Congressional power to declare war is subservient to the UN? You lost me here. What if Congress wants war either way? The war powers resolution didn't specify that Bush could only fight if the UN said ok. It said he could "use the Armed Forces of the United States as he determines to be necessary and appropriate". Now you're saying that if the UN says no, Congress magically loses its war powers? And you're the one claiming to care about the Constitution here?
I, personally don't want to go to war under a UN order.
So you're in the military? Allow me a brief time-out to thank you for your service then.
I want to go as an American nation under the powers of it's national constitution.
And you will be. (And Godspeed sir, and good luck.) Congress used its war powers to authorize military force, as is its right under the US constitution. Which part don't you get?
Everything Congress does has to be based in constitutional authority because (please read carefully here) the legislative branch was created by the constitution. Do you understand?
1-8-11 authorizes Congress to declare war. A declaration of war has a form. This legislation is not it. I'm so glad you're willing to overlook little nicities like form and citation of constitutional authority. Why, that means we have a living constitution and fully within the power of the branches, authorized by God Himself, to determine what they want it to allow them to do.
That means I won't be burdened with being a responsible American much longer; I can just turn the whole shebang over to the legislative, executive and judicial folks. Hey, why do we need a constitution, anyway? We got the UN, don't we?