Following the terrorist attacks of 9/11, Congress passed the Authorization to Use Military Force (AUMF), which granted the President the authority "to use all necessary and appropriate force against those ... [who] planned, authorized, committed, or aided the terrorist attacks" against the United States. Soon thereafter, President Bush issued a military order formulating guidelines for the detention and treatment of foreign belligerents captured in the "war on terror" and establishing military commissions to try some detainees for violations of the law of war. Beginning in early 2002, the United States began transferring suspected foreign belligerents captured in the "war on terror" to the U.S. Naval Station in Guantanamo Bay, Cuba for preventive detention and potential prosecution for any war crimes they may have committed. In 2004, the Supreme Court issued two key rulings concerning the Executive's authority to detain persons in the "war on terror." In Hamdi v. Rumsfeld , a majority of the Court found that the 2001 AUMF permitted the preventive detention of enemy combatants captured during hostilities in Afghanistan, including those who were U.S. citizens. A divided Court found that persons deemed "enemy combatants" have the right to challenge their detention before a judge or other "neutral decision-maker." The Hamdi case concerned the rights of a U.S. citizen detained as an enemy combatant, and the Court did not decide the extent to which this right also applied to noncitizens held at Guantanamo and elsewhere. However, on the same day that Hamdi was decided, the Court issued an opinion in the case of Rasul v. Bush , holding that the federal habeas corpus statute, 28 U.S.C. § 2241, provided federal courts with jurisdiction to consider habeas corpus petitions by or on behalf of persons detained at Guantanamo. The Court's rulings in Hamdi and Rasul had two immediate consequences. First, the Department of Defense (DOD) established Combatant Status Review Tribunals (CSRTs), an administrative process to determine whether a detainee at Guantanamo was an "enemy combatant." Second, the U.S. District Court for the District of Columbia began to hear the dozens of habeas cases filed on behalf of the detainees, with different judges reaching conflicting conclusions as to whether the detainees had any enforceable rights available other than the bare right to petition for habeas . After the Supreme Court granted certiorari to hear a challenge by one of the detainees to his trial by military tribunal, Congress passed the Detainee Treatment Act of 2005 (DTA) . The DTA requires uniform standards for interrogation of persons in the custody of the DOD, and expressly bans cruel, inhuman, or degrading treatment of detainees in the custody of any U.S. agency. At the same time, however, it divested the courts of jurisdiction to hear challenges by those detained at Guantanamo Bay based on their treatment or living conditions. The DTA also eliminated the federal courts' statutory jurisdiction over habeas claims by aliens challenging their detention at Guantanamo Bay, but provided for limited appeals of status determinations made pursuant to the DOD procedures for CSRTs, along with final decisions by military commissions. However, in the 2006 case of Hamdan v. Rumsfeld , the Supreme Court interpreted the provision eliminating federal habeas jurisdiction as being inapplicable to cases that were pending at the time the DTA was enacted, permitting it to review the validity of military commissions established pursuant to President Bush's 2001 military order. The Court held that the military tribunals established by the President did not comply with the Uniform Code of Military Justice (UCMJ) or the law of war which the UCMJ incorporates, including the 1949 Geneva Conventions. In response to the Hamdan ruling, Congress enacted the Military Commissions Act of 2006 ("MCA" or "2006 MCA"). The act authorized the President to convene military commissions to try "unlawful alien combatants" for war crimes without complying with the parts of the UCMJ the earlier system was said to violate, and it also established procedural requirements for the commissions. Finally, the MCA expressly eliminated court jurisdiction over all pending and future causes of action by detainees, including habeas review, with the exception of the limited review process established under the DTA. The complete elimination of habeas corpus review by Congress compelled the courts to address directly an issue they had avoided reaching in earlier cases: Does the constitutional writ of habeas corpus extend to noncitizens held at Guantanamo? The Constitution's Suspension Clause prohibits the suspension of habeas corpus except when public safety requires it in the case of invasion or surrender. The MCA did not purport to be a suspension of habeas , and the government did not make such a claim to the courts. Instead, the government argued that noncitizens detained at Guantanamo are entitled to no constitutional protections, including the privilege of habeas corpus . Therefore, it was argued, denying these persons access to habeas review would not run afoul of the Suspension Clause. In the 2008 case Boumediene v. Bush , the Court rejected this argument in a 5-4 opinion, and ruled that the constitutional privilege of habeas extends to Guantanamo detainees and cannot be extinguished by statute unless an adequate substitute is provided. As a result of the Boumediene decision, detainees currently held at Guantanamo may petition for habeas review of their designation and detention as enemy combatants. The judicial process established by the DTA was effectively nullified by a D.C. Circuit's ruling in January 2009 interpreting the Boumediene decision, although Congress has not officially repealed it. Several legal issues remain unsettled, including the scope of habeas review available to detainees, the remedy available for those persons found to be unlawfully held by the United States, and the extent to which other constitutional provisions extend to noncitizens held at Guantanamo and elsewhere. Some of these issues were expected to be addressed by the Supreme Court this term in an appeal of a D.C. Circuit panel ruling in the case of Kiyemba v. Obama , in which the appellate court held that federal habeas courts lack the authority to order the release of Guantanamo detainees into the United States, even when those detainees are found to be unlawfully held and the government is unable to effectuate their release to a foreign country. After the Supreme Court granted certiorari to review the case, several countries agreed to resettle the Kiyemba petitioners. In March 2010, the Supreme Court vacated the appellate court's decision and remanded the case back to the circuit court for further consideration in light of these developments. On January 22, 2009, President Obama issued an Executive Order requiring that the Guantanamo detention facility be closed as soon as practicable, and no later than a year from the date of the Order. The Order further requires specified officials to review all Guantanamo detentions to assess whether the detainee should continue to be held by the United States, be transferred or released to a third country, or be prosecuted by the United States for criminal offenses. During the review process, the Secretary of Defense was required to take steps to ensure that all proceedings before military commissions and the United States Court of Military Commission Review were halted. Although the imposed deadline for closing the Guantanamo detention facility was not met, the Obama Administration maintains that it intends to close the facility as expeditiously as possible. The closure of the Guantanamo detention facility and its resulting effects could have implications for legal challenges raised by detainees , particularly if detainees are brought to the United States, where they would arguably have a more clearly defined entitlement to additional constitutional protections. In March 2009, the Obama Administration announced a new definitional standard for the government's authority to detain terrorist suspects, which no longer employs the phrase "enemy combatant" to refer to perso ns who may be properly detained, although the new standard is largely similar in scope to the "enemy combatant" standard used earlier. The Obama Administration standard would permit the detention of members of the Taliban, Al Qaeda, and associated forces, along with persons who provide "substantial support" (rather than merely "support") to such groups, regardless of whether these individuals were captured away from the battlefield in Afghanistan. The Obama Administration indicated that this definitional standard does "not rely on the President's authority as Commander-in-Chief independent of Congress's specific authorization." The scope of the Executive's detention authority has been subject to ongoing litigation and conflicting rulings. In January 2010, a D.C. Circuit panel held in the case of Al-Bihani v. Obama that support for or membership in an AUMF-targeted organization may be independently sufficient to justify military detention, without proof that the detainee committed any hostile act. In discussing the scope of the Executive's detention authority, the panel applied the standard that had been used by the Bush Administration rather than the slightly more limited standard applied by the Obama Administration, and disavowed the view that international law has relevance to the determination. The significance of this policy change and the circuit court's ruling remains to be seen. As of March 2010, reviewing courts have ruled that at least 11 detainees are lawfully held pursuant to the AUMF, while at least 33 have been held to be (or were conceded by the government to be) held without authorization. Also in January 2010, the Obama Administration reportedly completed its assessment of the nearly 200 detainees remaining at Guantanamo, determining that about 50 detainees will continue to be held without trial; that around 35 detainees will be prosecuted in military commission or federal court; and that suitable countries have been found to take the remaining detainees. However, the transfer of 30 detainees of Yemeni nationality back to Yemen was stymied because an Al Qaeda affiliate in Yemen is suspected to have been behind the Christmas 2009 bombing attempt.