On the surface that does make sense, but I am not a lawyer or constitutional scholar. It is clearly a complex and ambiguous constitutional issue that would be fleshed out by the Supreme Court. In the modern era, what the constitution appears to say plainly, and what federal laws simply say, cannot be relied on until it has been reviewed by the Supreme Court. Moreover, like
@Brett327 alluded to, junior officers have no need to stress over this
Anyone who thinks they are going to wake up tomorrow morning and find the US at war with Denmark or Marines storming the beaches of Greenland without legal challenge, worldwide public protest, and political debate is naive. No Air Force captain is ever going to have to worry whether or not his orders to bomb the Greenland Customs House, no matter how tragically insane, are legal. It will be understood well before then.