Fudd, the SCOTUS accepts in the decision, not only that we are at war, but that this war could last 50 years. It's in Kennedy's majority opinion.
He doesn't care. He expects the USA to pay a little more, to go a little farther, to extend habeas corpus rights to all people detained by our government, in order to let the DC circuit court decide whether or not someone is an enemy combatant in this time of war.
The whole decision is about what to do with prisoners be they at Gitmo or at Leavenworth, Kansas.
I recommend you read the decision. Everyone seems to believe we're at war except you.
I recommend you also read the decision, and particularly the parts which discuss the Secretary of the Navy's implementation of the DTA, turning the impartial tribunals into kangaroo courts. If you want to blame someone, don't blame Kennedy but rather that idiot suit of a secretary of the Navy Winters.
And obviously the US government and that is the problem. If you don't even have enough confidence in your objectives to come right out state what you want to do, then you're in trouble. It would have taken a mere request by GB in the days following 9/11 to get a declaration of war. It's something that would have helped unite the nation and keep it united, which is absolutely essential when you're fighting a war of attrition. Instead he went around talking about some mythical "religion of peace".
The details of this particular case are inconsequential. It's just plain bad law, but it's the kind of thing that happens when you allow a war to become so unpopular. If we were clearly winning this war and Bush's approval ratings were up in the 70's this case never would have gotten to the high court.