> AUMF is NOT a Declaration of War.

A law passed by Congress authorizing acts of war is, ipso facto, a declaration of war (in the sense of an exercise of the Constitutional power to declare war.)

The only effect of not using specific legal phrasing is that it may not trigger other effects under other statutes Congress has passed which require particular language in subsequent law to trigger their effects. This can be important, to be sure, but it doesn't make it any less a declared war.

Open-ended declarations of war are, of course, extremely problematic and open to abuse, which is one of the reasons the last notable one (the Gulf of Tonkin Resolution) was repealed.

I guess we get to learn the lessons of the Vietnam era all over again in this generation. Maybe this time they'll stick...

Actually, a war was declared. An AUMF is a term the US Congress uses to declare war.

Actually, it wasn't.

"While the AUMF did not officially declare war, the legislation provided the President with more authority upon which to exercise his constitutional powers as Commander in Chief."

http://www.law.cornell.edu/wex/commander_in_chief_powers

As I said, it's a term they use. For example, see Vietnam, Gulf War, and Iraq War. Congress can declare war in different ways.

The last "officially" declared war was WWII, I believe.