in two areas. The first challenge by lawyers for a number of detainees goes to the heart of the detainment question - can persons be detained at all unless criminal charges are filed against them, or unless they are detained solely as PW/POWs under GC III ?

Obama challenged anew on detention
Saturday, March 21st, 2009 6:21 am | Lyle Denniston
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Conceding that the Obama Administration has made “a partial retreat” from Bush Administration claims of power to detain indefinitely individuals rounded up in the “war on terrorism,” lawyers for a group of detainees argued on Friday that the new government is still asserting too much authority. The President, they contended, is engaging in “impermissible law-making” by the Executive Branch, intruding on Congress’s powers.

President Obama’s new claim, outlined a week earlier by the Justice Department, remains ”a marked departure from and expansion of the military detention authority recognized by the traditional law of war,” just as that of the Bush Administration was, according to the new filing Friday in U.S. District Court.....
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The new leaders of the Justice Department contended that, while no longer asserting “inherent” presidential power to detain without charges, the President has authority under the resolution Congress enacted after the Sept. 11, 2001, terrorist attacks.
The detainee's filing (in response to the DoJ memo extensively covered in posts above) is here.

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The second challenge goes to the end game of the habeas process - that is, what remedies can a court order when it has found that a detainee should no longer be detained. Primarily, this is an Uighur issue.

New pressure in Uighurs’ cases
Saturday, March 21st, 2009 5:31 am | Lyle Denniston
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Seeking to put new judicial pressure on the Obama Administration to end the detention of Chinese Muslim (Uighur) detainees at Guantanamo Bay, lawyers on Friday asked a federal appeals court to hold Defense Secretary Robert M. Gates in contempt for doing nothing to free those prisoners — in one case, for nine months.

If Gates does not obey earlier court orders to take action, the two motions filed in D.C. Circuit Court argued, he should be brought into court promptly to go over possible punishment — including, as one suggestion, a fine of up to $500,000 a day until he obeys.
The two detainee filings are here and here.