"Yeah, we're at war. Anything else is just weaseling. But hey, our weasels are the good weasels, not like those awful weasels in Europe."

All weasels a bad: they affect the thinking ability of human adults:)
It seems to me that the Congress controls any war by the amount of money it will spend. If congress gives the money, then it's declared it's support for a war. Of course, this isn't clearcut- for example, a president can bypass this check- by getting money by other means [Iran-contra for example] or Congress could decide it wants to micro-manage "how" a war is run by bargaining for power by promises of money [which of course counters the intention of Constitution].