On September 20, President Bush addressed a joint session of Congress and the nation. He discussed his administration's diplomatic and military answers to the terrorist attacks of September 11. The president called the attacks "an act of war," but he did not ask Congress to approve a formal declaration of war.

In his speech to a nationally-televised joint session of Congress this past Thursday evening, President Bush told Americans how the government plans to respond to the terrorist attacks against the United States on September 11. As part of those responses, he said the United States would use the tools of diplomacy, intelligence, and law enforcement and "every necessary weapon of war" in a "long campaign" against the terrorists.

Under the U.S. Constitution, presidents serve as commander-in-chief of the American armed forces. But it is Congress, which can declare a state of war. The Framers felt putting the authority to declare war in the Congress restrained and checked the powers of the presidency.

Perhaps as a result, formal declarations of war are rare in the nation's history once in the War of 1812 against Great Britain; once against Mexico in 1846; against Spain in 1898; against Germany in 1917; and twice in 1941 one declaration against Germany and Italy, and another against Japan.

But since December of 1941, when President Franklin D. Roosevelt asked for it, the U.S. Congress has not formally declared a state of war although American combat troops have been deployed all over the world.

In 1950, following World War II, U.S. troops joined other nations under the auspices of the United Nations to help repel the invasion of South Korea by troops from the North. President Harry S. Truman used a United Nations resolution to send American forces with congressional acquiescence. During the Vietnam War of the 1950s, 60s, and 70s, Congress approved the use of force when it passed the Gulf of Tonkin Resolution in 1964.

Both in Korea and Vietnam, says Donald L. Robinson, Professor of Government at Smith College in Massachusetts, there was no formal declaration of war. "It was not used in Korea, and it was not used in Vietnam,? said Mr. Robinson. ?In Korea, President Truman relied upon a U.N. resolution, and in Vietnam, President Johnson relied upon the Gulf of Tonkin Resolution, which gave him power to repel communist aggression in Southeast Asia by all necessary means, more or less a blank check but not a declaration of war."

During the Persian Gulf War of 1991, President George Bush, father of the present incumbent, sought congressional approval for U.S. forces to fight against Saddam Hussein. "This Congress has justifiably exercised its prerogatives under the Constitution to decide between war and peace,? said Representative Bob Toricelli. ?With it comes a great responsibility. My colleagues exercised that constitutional responsibility wisely."

In 1991, Representative Bob Toricelli, now a U.S. Senator, spoke in the House of Representatives after the House passed a resolution approving the use of force against Iraq by a vote of 250-183. In the U.S. Senate, it was much narrower, 52-47. Following the close vote, Senator Robert Byrd of West Virginia, was somber in his assessment of what Congress had just authorized and determined to create unity with which the country would face war. "It is now time to unite, and the support for the brave men and women of our armed forces who will prosecute the struggle and carry the Alliance to ultimate victory," said Senator Byrd.

Former Speaker of the House Thomas Foley called the congressional vote, "a practical equivalent" of a declaration of war. But James Thurber, Director of The American University's Center for Congressional and Presidential Studies, says there is a reason why Congress now uses authorizations of force instead of formal declarations of war. "Under a declaration of war, Congress gives the president a great deal of power. And indeed, without another act, it is hard to take that power back,? says Mr. Thurber. ?And that is one of the reasons they are reluctant to move in haste to give him a declaration of war."

Since 1973, Congress and the president have tried to cooperate when American troops are fighting abroad. A law called the War Powers Act was passed that year over the veto of then-President Richard Nixon. The law in essence made the president and Congress partners in the prosecution of war. James Thurber further explains. "The War Powers Act requires reports to Congress about what happens after troops have been deployed abroad. There have been eighty-four reports to Congress through 2001 about troops being deployed overseas,? he says. ?So, in other words, they want to give him support but they also want to have him consult with them. They need to express their views over time, and if he fails, they criticize him so they have it both ways."

The tensions between Congress and the presidency over the use of American forces in Asia, the Middle East, Africa, Central America and Europe, echoed some doubts over policy, and the institutional conflict remains. But while Congress has reflected public ambivalence to overseas missions with goals that were ambiguous and commitments left open-ended, public opinion in the wake of the terrorist attack of September 11, is loud and clear.

Perhaps that's why in the present crisis, the U.S. Congress quickly responded to President Bush's call for fiscal authorization to respond to the terrorist attack. The U.S. Senate voted 98-0 to support a $40 billion package to fund security, law enforcement and rescue efforts under the direction of the president. Even with the huge majorities in Congress approving the resolution backing the president, some members of Congress still think a declaration of war should have been passed.

Representative Robert Barr, Republican of Georgia, says that if the terrorist acts were, as the president put it, "acts of war," then the proper answer should have been a congressional declaration of war, not an authorization to use force. "In December of 1941, almost exactly 60 years ago, our nation last took the ultimate and final step to secure peace and to seek appropriate retribution for attacks on this country,? says. Mr. Barr. ?On December 8, 1941, our nation declared war in response to acts of war committed against it. And the response to a state of war is a declaration of war."

But it is highly unlikely Congress would approve such a declaration of war. There are those who think such a declaration may never come again. But Donald L. Robinson, Professor of Government at Smith College in Massachusetts, says it is not impossible. "War would be declared where an attack was made against the United States by an enemy nation,? he says. ?And I'm not ready to say that will never happen."

As in past crises, the president and Congress have rallied together. It doesn't seem to matter to the American people how Congress gives its support to the president, whether through a declaration of war or an authorization to use force. The important thing, polls show, is that both branches of government are united in a common cause against an enemy that means the country harm.