The 1973 War Powers Act requires a President to notify Congress within 48 hours of launching military action, limits U.S. armed forces involvement to 60 days without congressional approval, and allows 30 days more for withdrawal. The law was passed over Presidents Nixon’s veto; every President since has maintained it is unconstitutional. Effectively, the law gives a President a free hand to do what he or she thinks best.
Constitutional or not the law has never been effective in limiting a presidents ability to wage war. The United States has been involved in many wars since 1973 with or without Congressional approval. The Wikipedia article cited gives a list of past crises involving war powers as well as a discussion of possible conflict with the Constitution.
Some believe that Congress can prevent a president from acting, possibly because:
- They believe the Constitution or the War Powers Act effectively curbs this.
- It seems reasonable.
Others, overly partisan, believe that President Obama is the first to claim the right as Commander in Chief to engage in war.
Presidents and Congress like the War Powers Act as Mark Thompson explains in the Time article cited: “Generally speaking, the President likes this, (The War Powers Act) since he doesn’t have to convince Congress of the wisdom of his war, and Congress likes it even more. Under the current system, lawmakers get to wink at the White House by passing an authorization for the use of military force or other purported justification as a fig leaf they can abandon if things go sour. A declaration of war demands more, and Congress is leery of going on the record with such declarations for its own political reasons.”
News reports indicate that British law is different: the approval of parliament is needed, and this provides a brake on any rush to war.