Many Members of Congress became concerned with the erosion of congressional authority to decide when the United States should become involved in a war or the use of Armed Forces that might lead to war. On November 7, 1973, Congress passed the War Powers Resolution ( P.L. 93-148 ) over the veto of President Nixon. The War Powers Resolution (WPR) states that the President's powers as Commander in Chief to introduce U.S. forces into hostilities or imminent hostilities are exercised only 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. Former Yugoslavia/Bosnia

The issue of war powers and whether congressional authorization is necessary for U.S. participation in U.N. action was also raised by efforts to halt fighting in the former territory of Yugoslavia, particularly in Bosnia. Section 8(a) of the War Powers Resolution states that authority to introduce U.S. forces into hostilities is not to be inferred from any treaty, ratified before or after 1973, unless implementing legislation specifically authorizes such introduction and says it is intended to constitute an authorization within the meaning of the War Powers Resolution. Kosovo

The issue of presidential authority to deploy forces in the absence of congressional authorization, under the War Powers Resolution, or otherwise, became an issue of significant controversy in late March 1999 when President Clinton ordered U.S. military forces to participate in a NATO-led military operation in Kosovo. This action has become the focus of an ongoing policy debate over the purpose and scope of U.S. military involvement in Kosovo. A war powers issue for years was whether the use of U.S. force in Iraq in the period after the early 1991 Desert Storm conflict had been authorized by Congress. On September 5, 1996, President Clinton reported to Congress on U.S. military actions in Iraq to obtain compliance with U.N. Security Council Resolutions, especially in light of attacks by Iraqi military forces against the Kurdish-controlled city of Irbil. Such actions, in the past, were reported under P.L. 102-1 would in the future be included in the reports required by P.L. Since he announced the end of major combat operations against Iraq on May 1, 2003, the President has made periodic reports on the current situation in Iraq "consistent with" P.L. As enacted, Section 8147 of P.L. On October 7, the President consulted with congressional leaders from both parties for over two hours on Somalia policy and also announced that U.S. forces would be withdrawn by March 31, 1994. In addition, on November 9, 1993, the House adopted H.Con.Res. 292 , expressing the opinion of the House, among other things, that "the President shall not deploy, establish or maintain the presence of units and members of the United States Armed Forces on the ground in Libya," except to rescue a member of the Armed Forces from imminent danger, and that the President shall within 14 days after passage of this resolution provide a report to the House detailing information about Operation Odyssey Dawn and Operation Unified Protector, and a report answering a number of questions detailing U.S. security interests and objectives, and the activities of United States Armed Forces, in Libya since March 19, 2011. Instances Formally Reported Under the War Powers Resolution

Presidents have submitted 132 reports to Congress as a result of the War Powers Resolution. The U.S. also continues to deploy military forces in support of the Multinational Force (MNF) in Iraq. Issues for Congress

An immediate issue for Congress when the President introduces troops into situations of potential hostilities is whether to invoke Section 4(a)(1) of the War Powers Resolution and trigger a durational limit for the action unless Congress authorizes the forces to remain. 107-243 ). Prior to using force under this statute the President is required to communicate to Congress his determination that the use of diplomatic and other peaceful means will not "adequately protect the United States ... or ... lead to enforcement of all relevant United Nations Security Council resolutions" and that the use of force is "consistent" with the battle against terrorism.
Two separate but closely related issues confront Congress each time the President introduces Armed Forces into a situation abroad that conceivably could lead to their involvement in hostilities. One issue concerns the division of war powers between the President and Congress, whether the use of Armed Forces falls within the purview of the congressional power to declare war and the War Powers Resolution (WPR). The other issue is whether or not Congress concurs in the wisdom of the action. This report does not deal with the substantive merits of using Armed Forces in specific cases, but rather with congressional authorization for military action, and the application and effectiveness of the WPR. The purpose of the WPR (P.L. 93-148, passed over President Nixon's veto on November 7, 1973) is to ensure that Congress and the President share in making decisions that may get the United States involved in hostilities. Compliance becomes an issue whenever the President introduces U.S. forces abroad in situations that might be construed as hostilities or imminent hostilities. Criteria for compliance include prior consultation with Congress, fulfillment of the reporting requirements, and congressional authorization. If the President has not complied fully, the issue becomes what action Congress should take to bring about compliance or to influence U.S. policy. A related issue has been congressional authorization of U.N. peacekeeping or other U.N.-sponsored actions.
For over three decades, war powers and the War Powers Resolution have been an issue in U.S. military actions in Asia, the Middle East, Africa, Central America, and Europe. Presidents have submitted 136 reports to Congress as a result of the War Powers Resolution, although only one (the Mayaguez situation) cited Section 4(a)(1) or specifically stated that forces had been introduced into hostilities or imminent hostilities. Congress invoked the WPR in the Multinational Force in Lebanon Resolution (P.L. 98-119), which authorized the Marines to remain in Lebanon for 18 months. In addition, P.L. 102-1, enacted in January 1991, authorizing the use of U.S. Armed Forces in response to Iraqi aggression against Kuwait, stated that it constituted specific statutory authorization within the meaning of the WPR. On November 9, 1993, the House used a section of the WPR to state that U.S. forces should be withdrawn from Somalia by March 31, 1994; Congress had already taken this action in appropriations legislation. War powers have been at issue in former Yugoslavia/Bosnia/Kosovo, Iraq, and Haiti. Authorizing military actions in response to the terrorist attacks against the United States of September 11, 2001, through P.L. 107-40 directly involved war powers. The continued use of force to obtain Iraqi compliance with U.N. resolutions remained a war powers issue from the end of the Gulf War on February 28, 1991, until the enactment of P.L. 107-243 in October 2002, which explicitly authorized the President to use force against Iraq, an authority he exercised in March 2003, and continues to exercise for military operations in Iraq. Most recently, issues associated with presidential compliance with the War Powers Resolution have arisen over his use of U.S. military forces to support a U.N. sanctioned "no-fly zone" in Libya, without obtaining congressional authorization for such action.
Debate continues on whether using the War Powers Resolution is effective as a means of assuring congressional participation in decisions that might get the United States involved in a significant military conflict. Proposals have been made to modify or repeal the resolution. None have been enacted to date. This report will be updated as events warrant.