The ongoing controversies surrounding President Barack Obama's use of drones to target "enemies" of the United States raises anew the question of the president's legal authority to conduct the war on terror.

It has broad implications, moreover, for the constitutional allocation of war powers and the responsibilities of Congress and the president in the management and conduct of this, or any, war.

Supreme Court decisions rendered at the dawn of the republic, never overturned and still good law, shine a bright light on a number of the legal issues that have arisen and point the way for Congress to regain control of the conduct of war. Let us consider a 101 primer on the constitutional governance of war, as seen through the eyes of the High Tribunal.

The court, echoing the aims of the framers of the Constitution, held in a string of early 19th century cases, that the president, as commander in chief, is empowered to prosecute war, once "authorized or begun." Congress, through the War Powers Clause, possesses the sole and exclusive constitutional authority to "authorize," that is, initiate war or lesser military hostilities against those whom it considers to be an "enemy" of the American people, through formal declaration of war or authorization of the use of force. But war may be "begun" through invasion of the United States. The court has consistently held that the president has no constitutional authority to initiate military hostilities but is empowered to "repel the invasion." Congress, alone, may identify "enemies" of the United States.

Once war has been commenced by Congress or begun through invasion, the president assumes authority to direct the course of war. The president enjoys discretion to conduct the hostilities, although Congress, as evidenced in history and law, retains authority to impose directions and instructions upon the president, which means that Congress, by statute, may control the conduct of the war. This reflects James Madison's statement that Congress has the authority to "commence, continue and conclude war."

How does President Obama's use of drones fare within this legal and constitutional framework? Setting aside the civil liberties concerns arising out of a presidential directive to kill an American citizen reported to have joined the enemy, it is clear that the president, barring congressional prohibition, is free to deploy weapons at his disposal, including the use of drones. In other words, Congress has the authority to constrain the president, if it wishes to do so.

The broader question of the legal basis for the conduct of war against al-Qaida is somewhat more complicated, but this issue, too, may be resolved by Congress.

Since the president, as the court has ruled throughout our history, lacks constitutional authority to initiate war, including lesser military actions, the chief executive is dependent upon congressional determinations of war and peace.

In the aftermath of the attack on America on Sept. 11, 2001, Congress enacted the Authorization to Use Military Force, which purported to authorize the presidential use of force against all those whom he determines to have participated in the attack, or otherwise aided, assisted or supported it. That measure provided the legal authorization for President George W. Bush's invasion of Afghanistan, which was the nation from which al-Qaida launched the attack on the United States.

But the inherent flaw in the statute - allowing the president to determine when, where and against whom to levy war - violates the doctrine of nondelegation, which prohibits Congress from transferring to the president its constitutional powers, including the appropriations power, lawmaking power and war power.

If Congress could transfer those powers, it could essentially rewrite the Constitution which, among other mischievous consequences, would undermine the amendatory provision of the Constitution and fundamental republican principles.

The vices of the statute are revealed in President Obama's decision to assert authority to expand military actions, including drone strikes, in Pakistan, Somalia and Yemen, places far removed from Afghanistan, but where the president has identified remnants of al-Qaida.

This reading of the legislation, thus far uncurbed by Congress, allows the president to make war by his own lights, which runs afoul of the War Powers Clause and the rationale that led the framers to vest the war power in Congress alone.

Congress should fix this problem by repealing AUMF and authorizing military actions against an enemy of its choosing.

Adler is the Cecil D. Andrus Professor of Public Affairs at Boise State University, where he serves as director of the Andrus Center for Public Policy. He has lectured nationally and internationally on the constitutional governance of war making.