THE most agonizing decision we make as a nation is whether to go to war. Our Constitution ambiguously divides war powers between the president (who is the commander in chief) and Congress (which has the power of the purse and the power to declare war). The founders hoped that the executive and legislative branches would work together, but in practice the two branches don’t always consult. And even when they do, they often dispute their respective powers.

A bipartisan group that we led, the National War Powers Commission, has unanimously concluded after a year of study that the law purporting to govern the decision to engage in war — the 1973 War Powers Resolution — should be replaced by a new law that would, except for emergencies, require the president and Congressional leaders to discuss the matter before going to war. Seventy years of polls show that most Americans expect Congress and the president to talk before making that decision, and in most cases, they have done so.

Congress passed the 1973 resolution in response to the Vietnam War. But it is ineffective at best and unconstitutional at worst. No president has recognized its constitutionality, and Congress has never pressed the issue. Nor has the Supreme Court ever ruled on its constitutionality. In fact, courts have largely shied away from refereeing war-powers disputes between the two political branches.

Most legal experts, however, interpret a 1983 Supreme Court decision on Congress’s authority to overrule the president to mean that parts of the statute are unconstitutional. Its provision saying that Congress may require the president to remove troops from combat merely by passing a concurrent resolution cannot survive the constitutional requirement that a measure must be presented to the president for signature or veto if it is to have the force of law.

The statute has other problems as well: it too narrowly defines the president’s war powers to exclude the power to respond to sudden attacks on Americans abroad; it empowers Congress to terminate an armed conflict by simply doing nothing; and it fails to identify which of the 535 members of Congress the president should consult before going to war.

As a consequence, the 1973 statute has been regularly ignored — a situation that undermines the rule of law, the centerpiece of American democracy.

Many have suggested that the war powers resolution be amended or replaced altogether. But proposals to do so haven’t gotten very far, typically because most have sided too heavily with either the president or Congress.

Our proposed new law, the War Powers Consultation Act of 2009, does not pretend to resolve the underlying constitutional issues — only a constitutional amendment or a Supreme Court decision could do that. It would reserve the ability of both Congress and the president to assert their constitutional war powers. In drawing up the statute we focused on a common theme that almost all past proposals shared: the importance of meaningful consultation between the president and Congress before the nation is committed to war.

Our proposed statute would provide that the president must consult with Congress before ordering a “significant armed conflict” — defined as combat operations that last or are expected to last more than a week. To provide more clarity than the 1973 War Powers Resolution, our statute also defines what types of hostilities would not be considered significant armed conflicts — for example, training exercises, covert operations or missions to protect and rescue Americans abroad. If secrecy or other circumstances precluded prior consultation, then consultation — not just notification — would need to be undertaken within three days.

To guarantee that the president consults with a cross section of Congress, the act would create a joint Congressional committee made up of the leaders of the House and the Senate as well as the chairmen and ranking members of key committees. These are the members of Congress with whom the president would need to personally consult. Almost as important, the act would establish a permanent, bipartisan staff with access to all relevant intelligence and national-security information.

Congress would have obligations, too. Unless it declared war or otherwise expressly authorized a conflict, it would have to vote within 30 days on a resolution of approval. If the resolution of approval was defeated in either House, any member of Congress could propose a resolution of disapproval. Such a resolution would have the force of law, however, only if it were passed by both houses and signed by the president or the president’s veto were overridden. If the resolution of disapproval did not survive the president’s veto, Congress could express its opposition by, for example, using its internal rules to block future spending on the conflict.

We believe our proposal is good for the presidency because it would eliminate a law that every president since Richard Nixon has treated as unconstitutional, while giving the president the political benefit of forcing Congress to take a position on going to war. And it would do so without insisting that the president get the consent of Congress.

The statute is good for Congress because the legislative branch would get a more significant role when the nation decides whether to go to war. Some may argue that Congress should have the dominant role in war powers debates. But it hasn’t played that role under the 1973 resolution. Rather than endorse any absolutist position, our statute would give Congress access to intelligence, a full-time staff for studying national security issues and a well-defined mechanism for consulting and voting on significant armed conflicts.

Finally, the statute is good for the country because it would enhance the prospects for cooperation between Congress and the president. It would ensure that the president received independent advice from Congress, and it would allow the people to hold Congress accountable for its role in the process.

When it comes to war, Americans deserve better than a law that is ineffective and ignored. They deserve a law that will encourage future presidents and Congresses to work together to protect our nation.