===United States intervention===
Under the [[War Powers Act]] of 1973 the U.S President has limited authority to use military force without Congressional authorization when there is an imminent [[national security]] threat, however President Obama made clear that he order the use of force out of alleged humanitarian concerns and not national security for other reasons. Members of Congress of both parties have expressed concern the President may have violated the law in doing so.<ref>http://rooney.house.gov/index.php?option=com_content&view=article&id=3190:rooney-resolution-president-should-obtain-congressional-authorization-or-end-military-campaign-in-libya-&catid=48:2011-press-releases</ref> The War Powers Act states that the President’s powers as Commander in Chief to introduce U.S. forces into hostilities or imminent hostilities can only be exercised pursuant to (1) a declaration of war; (2) specific statutory authorization; or (3) a national emergency created by an attack on the United States or its forces. The War Powers Act requires the President in every possible instance to consult with Congress before introducing American Armed Forces into hostilities or imminent hostilities unless there has been a declaration of war or other specific congressional authorization. None of these prerequisites have been met.
On March 21, 2011, President Obama announced that U.S. military forces had commenced operations in Libya two days earlier on March 19 "to prevent a humanitarian catastrophe" citing UN Resolutions as the authority to do so. However, the Charter of the [[United Nations]], in Article 2(4), prohibits the “threat or use of force against the territorial integrity or political independence” of a member state under most circumstances, and many practitioners and observers have wondered whether the establishment of a no-fly zone would constitute a violation of this prohibition. The Congressional Research Services advised if a no-fly zone were to be imposed against a state that has not carried out an armed attack against its neighbors, that state may consider the imposition of a no-fly zone as an “armed attack.” CRS warned that even if the no-fly zone operations in a given state do not constitute an “armed attack",