I don't know, but they sure are leaving their options open. And hey, that's not conspiracy talk; it's what the chair of the Joint Chiefs says.
These weekly updates serve two purposes, it seems to me. First, it desensitizes Americans to the subject, so that if and when they wake up to hear, "The U.S. last night began bombing key Iranian weapons depots," they won't be shocked.
Second, these little trial balloons give the government more information about the likely reaction should they start bombing. I think libertarians sometimes overrate the power of the government. For all their guns and money, let's remember that there are a at most a few hundred key people in Washington running the show, and really you could whittle that number down to under 50 if you wanted to raise the threshold on your definition of "power."
Their control of millions of Americans and (less) control of billions of Earthlings rests on widespread perceptions of not only legitimacy but also obedience from everybody else. If the 50 people running the show in DC really overstepped, the jig could quickly unravel. That's why they spend so much time manipulating public opinion; it is crucial to their efforts.
(If you have never read it before, I strongly encourage you to read at least the first 5 pages of Rothbard's Introduction to Etienne de La Boetie's The Politics of Obedience: The Discourse of Voluntary Servitude.)
So what does this mean, folks? It means that if you don't want your "representatives" to give the green light to blow up some more foreigners, then you should let that opinion be known. I'm not saying write a letter to your congressperson (though you can do that if you want). I'm more saying, let your friends and neighbors know that you think it's a nutjob idea. If you don't want to sound like a wuss, couch your objection in terms of the marooned U.S. troops in Iraq who could be really screwed if all the countries in that region said, "Oh, so that's how it's going to be, eh?"
(BTW I'm not just making stuff up. I've heard pro-military people speculating about supply lines being cut off etc. if Iran really declared all-out war with the U.S.)