What is legal for the president to do would come down to what the Supreme Court decided a "War Powers Resolution " is- besides cowardly fluff.
If they decide it is just a statement that the president is able to act under his pre-existing "repel sudden attacks" power, and that is the most common explication one finds, then the media will have used the jealousy and cowardice of our judges and elected officials to produce President Hillary going from her signing in ceremony to the Oval Office to sign a pardon for ex-president Bush and to sign the new law given her carte-blanche to conduct war.
OTOH it's Christmas, when we're all reminded miracles can happen.
For what it's worth, the guy I saw on TV said that it wasn't even close, it was a slam dunk for the Pres on this issue.
Let's face it, if Osama bin Laden calls the US, the President has the power to listen in, and he doesn't need a court order. Napolitano's argument, by the way was so absurd. He said that the President should get a court order, and it would only take him about 15 minutes to do so. Give me a break. What's the President going to do, tell Osama "All lines are busy, please call back in 15 minutes?" I can't believe anyone would be so stupid as to make such an argument. You need to be able to get a court order in one second, or to simply take the call without a court order.