I keep hearing arguments (most recently in the treason thread) that various war-time powers — for instance, the power to punish people for treasonously aiding our enemies — are applicable only if the war is declared.
No no no. Did I say, "no"? Just in case, "no." That is not and has not been U.S. law. I canvassed the caselaw on this here, but the short answer is that U.S. law has not treated our undeclared wars (e.g., the Civil War, the Korean War, the Vietnam War) differently from declared wars (e.g., World War I or World War II).
I realize that some people might argue that the law should distinguish declared wars from undeclared wars. But they should acknowledge that this is a change from longstanding American legal understanding, and they should also discuss how this would apply in situations where wars have generally not been declared (e.g., civil wars, wars in which we're attacked and conduct takes place before we have time to declare war, and so on).
But beyond this, the war against Iraq is a declared war. A declaration of war doesn't require magic words: A Congressional authorization to the President to use military force suffices. I blogged more about this here; but note in particular that Joe Biden, the drafter of the authorization of the use of force following Sept. 11, specifically said that he viewed it as a declaration of war. And the Iraq war is authorized by a very similar authorization of the use of force.
So the war has been declared; and even if it hadn't been declared, it would have still been a war for legal purposes.