Yeru:
While, with the way our nation operates, Congress authorizing use of force is effectively treated as declaring war, it is not recognized as a formal declaration of war by the international community at large.
Proof of point is that these naval actions - certainly effectively blockades - are never refered to as such.
The *proper* thing to do is write out a full, formal, declaration of war against the nations we wish to target (or, even, the people or groups, as was the case with the pirates of the Barbary coast in the 1800s) and then declare that certain ports are blockaded.
The point is that a state of war must exist, and the port must be DECLARED as being blockaded for these actions to be 'legal'. The declaration of blockade is a very important point.
IF these were really for Yemeni regular army troops why were the SCUD parts hidden under sacks of cement?
Let's see, why would a nation want to resupply its army without everybody in the world (especially their local immediate threat governments) knowing? Hmmm...let me think.....