The point is, in any other situation, the government must present its case that a citizen engaged in wrongdoing, and the citizen has the right to challenge accusers and rebut evidence. It's called due process. Otherwise, any President would gain the power to declare someone an enemy combatant and there would be no recourse, no review for that person. Are you really sure you want such a precedent set?
Like I've said, have a hearing, have both sides present their case, and if the government makes its case, may the citizen in question wish he had died on the battlefield...
A - The government says so.
The government says a lot of things. Hamdi is an American citizen, and until the executive branch can prove their case, he should be entitled to a fair (even if closed) hearing.
Then hang him.
Then use that in court and prove it, don't just hold a man without charges, that is exactly what ole King George used to do...and even then Parliment usually sided against him....where is Congress?
A lot, actually. Unless those things are now Unconstitutional.