On whether the court has authority to decide the issue:

...The Constitution places affirmative limits on the power of the Executive to act, and these limits apply in times of peace as well as times of war...Heedlessly to refuse to hear constitutional challenges to the Executive’s conduct in the name of deference would be to abdicate this Court’s responsibility to safeguard the rights it has sworn to uphold. ...this Court gives appropriate and due deference to the executive and legislative branches–and understands the limits of its own (and their) role(s). But due deference does not eliminate the judicial obligation to rule on properly presented constitutional questions. Courts must safeguard core constitutional rights. ...Although it is true that there are scattered cases–primarily decided during World War II–in which the Supreme Court sanctioned undue deference to the executive and legislative branches on constitutional questions, those cases are generally now considered an embarrassment (e.g., Korematsu v. United States, 323 U.S. 214 (1944) (upholding the internment of Japanese Americans based on wartime security concerns)), or referred to by current members of the Supreme Court (for instance, Justice Scalia) as “wrong” (e.g., Ex parte Quirin, 317 U.S. 1 (1942) (allowing for the military detention and execution of an American citizen detained on U.S. soil)). Presented, as this Court is, with unavoidable constitutional questions, it declines to step aside.

On the vagueness of the term "associated forces" which the Government claims is defined by the Laws of War:

As the Supreme Court said in Hamdi, the laws of war are not and should not be part of the domestic laws of the United States. In addition, however, “associated forces” is an undefined, moving target, subject to change and subjective judgment.

Judge Forrest says the provision(Section 1021(b)(2))violates the First, Fifth, and Fourteenth Amendments of the United States Constitution.

Among the reasons a permanent injunction is warranted:

Imprisonment without trial and for an indefinite period certainly constitutes irreparable harm.

On the balance of hardships:

The Government already has ample authorization to pursue those actually involved in the attacks on September 11, 2001, and it has a host of criminal statutes (referred to above) that it can use to prosecute those who engage in a variety of activities that endanger lives or constitute terrorism. ...Most importantly, since Congress may pass no law abridging rights guaranteed by the First Amendment, enjoining enforcement of a statute that does just that cannot deprive Congress or the executive branch of that which they have no right to have. According to the Government, § 1021 is merely a reaffirmation of the AUMF--a position with which the Court disagrees. If, however, the Government is taken at its word, then enjoining its ability to enforce S. 1021(b)(2) removes no tools from the Government’s arsenal.

We need more judges who realize that due deference does not require a rubber stamp of approval.