[elif]

It is legally an indefinite detention pending formal charges, but due to the nature of "indefinite," those charges never have to actually exist.

It performed under section 1021 of the original National Defense Authorization Act (NDAA 2012), which has been upheld as constitutional by an appellate court, a ruling which the supreme court declined to subsequently hear.

https://en.wikipedia.org/wiki/Hedges_v._Obama

[mikecb]

This is not a detention under the NDAA. This case has nothing to do with the NDAA. Further, Obama's signing statement of that law stated that his Administration believed such provision to be unnecessary and unconstitutional:

"Moreover, I want to clarify that my Administration will not authorize the indefinite military detention without trial of American citizens. Indeed, I believe that doing so would break with our most important traditions and values as a Nation. My Administration will interpret section 1021 in a manner that ensures that any detention it authorizes complies with the Constitution, the laws of war, and all other applicable law."

Hedges v. Obama did not affirm the constitutionality of that law, but rather that that plaintiff did not have a sufficient interest in that provision in order to ensure that they would present the best case that can be made, which is important because US Court's follow precedent. If you'd like to read more, look for the constitutional requirement of Standing.