Parse the response. It won't take long.

"These are unlawful combatants." Are they? The point of a trial, or some sort of evidentiary hearing that assures due process, is to answer that question, hopefully with some degree of certainty. Until that happens, they are only accused, and given the number of detainees who have been released during the last few years, there is reason to wonder whether the administration ever makes an accurate accusation. Six years of detention without a trial on the strength of an unproved charge. This is what you're defending, Senator McCain?

"They are not American citizens." They are held in American custody. Article I, section 9 of the Constitution limits the power of Congress to suspend the writ of habeas corpus. The constitutional text does not restrict the writ's availability to citizens. While Justice Kennedy's opinion concluded that "the citizenship and status of the detainee" is relevant to the breadth of the Suspension Clause, it gave greater weight to "status" than to "citizenship." The real question is whether they are enemy combatants; if not, the government has no authority to detain them, citizen or not. The right to habeas corpus guarantees a fair procedure to determine that the detainees are actually enemy combatants.

"I think we should pay attention to Justice Roberts' opinion." Chief Justice Roberts wrote a dissenting opinion. The dissent tells us what the law is not. Don't you think, Sen. McCain, it would be better to pay attention to what the law is?

Compare Obama's response to McCain's and ask yourself how, in good conscience, anyone would want to give McCain the power to shape the Supreme Court?