He's going to use a loophole, and despite the "two weeks" announcement, he's going to claim, after he gives the order, that the situation was a 'clear and present damger", and he acted in his capacity as commander in chief, to protect the US.
He doesn't need to declare war to nuke another country. It is possible this weekend he will strike the mountain under which the main nuclear facility exists.
But it will not affect that facility because it is too underground.
He is waiting for the weekend to decrease effects on the global markets.
