Apparently so. I view it this way: The Constitution does not expressly prohibit the President from using the military in the absence of a declaration of war. Such use -- as, for example, in the Barbary Wars -- by Jefferson and Madison indicate that neither the author nor his contemporaries interpreted it to impliedly contain such a prohibition either. Instead, it has always been assumed that the President had authority to act militarily without a declaration of war, and this assumption is carried forward and codified in a sense in the War Powers Resolution, which takes the President's authority to act first as a given. There seldom is much dispute about it, but as I indicated earlier: I believe the courts would leave resolution of such an issue to the executive and legislative branches based on the political question doctrine.