Basically, a Federal Judge has enjoined enforcement of Sec. 1021 of the NDAA, discussed here. The Court found that --despite the Government's argument that the NDAA did nothing more than reaffirm the AUMF-- the vague language of the NDAA as to who qualifies as a "covered person" capable of detention stretches beyond who would be a "covered person" under the AUMF.
As stated in the decision:
First, by its terms, the AUMF is tied directly and only to those involved in the events of 9/11. Pub. L. 107-40, 115 Stat. 224 at § 2(a) (authorization of the president to use force related to “attacks that occurred on September 11, 2001); see also id. at Preamble (“Whereas, on September 11, 2001, acts of treacherous violence were committed against the United States and its citizens . . .”). Section 1021, in contrast, has a non-specific definition of “covered person” that reaches beyond those involved in the 9/11 attacks by its very terms.
Considering that this should have been the real concern about the NDAA's detention provisions to begin with --rather than the hand-wringing about American citizens arrested in the United States-- I think the decision is exactly right.
The decision can be found here.