It is an urgent and emphatic statement by President Bush, and had it been uttered in the previous century and under different circumstances, its meaning would be crystal clear.
But as the president himself has said, this is a "new kind of war," and so the American public, Washington's allies, and even its enemies are left wondering what exactly the stepped-up war rhetoric of recent days signifies.
Foremost, say military and foreign-policy analysts, it should be interpreted as a message designed to cement support at home and abroad for a long, difficult campaign against terrorists.
In this case, war should also be understood to involve other tools besides the military, including diplomacy, finance, and economics - as well as the uncertainty of not knowing who or where the enemy is.
But, these experts add, the war talk should also be taken at face value. US military action is to be expected once an international coalition has been formed, targets have been identified, and a military support structure is in place. Not only could this involve an on-the-ground effort to capture terrorist Osama bin Laden, it could include strikes against targets in countries that harbor terrorists.
"I think the rhetoric is aimed at multiple audiences, the first of which is the American public," says Raymond Tanter, who worked on security issues in previous GOP administrations.
Polls show the American public, actually, is already on board with the idea of military action, with a Washington Post-ABC News poll indicating more than 90 percent of Americans support military action against the groups or nations responsible for Tuesday's attack.
"There is no question America is rallied and ready," says presidential spokesman Ari Fleischer. But the president is also preparing the public for a long road, asking for "patience" because "the conflict will not be short."
The war message, however, is also aimed at those beyond American shores, including those states that harbor terrorists, or those nations that border such states -such as Pakistan. Indeed, the rhetoric seems to have already had an effect on Pakistan, which has agreed to a list of US requests for support -including, reportedly, use of air space.
Secretary of State Colin Powell says he sees an opening for improved ties with Iran and Syria, after those countries condemned last week's attack and called for antiterrorism cooperation.
Principally, the US is in a "diplomatic effort" to build a worldwide coalition to go after terrorists, says Gen. Wesley Clark, former NATO Supreme Commander. "What's important, is that the world knows it has the backing of US military might," he said on TV over the weekend.
But beyond the intent of building support, the war rhetoric has meaning in itself for exactly what it implies: military action.
Indeed, Mr. Bush has called up 35,500 reservists for active duty to help protect home turf in America; has won the overwhelming approval of Congress for use of military force; and has warned Americans that they should go about their business today "with a heightened sense of awareness that a group of barbarians have declared war on the American people."
While the administration is keeping the public - and its enemies - guessing about its exact plans, several scenarios are floating in Washington and on the country's television airwaves.
One is that the president will approve covert action that would allow for the assassination of terrorist leaders such as Mr. bin Laden, whom Bush has named a "prime suspect." Endorsing assassinations would be a departure from previous US policies. But it would help clear the way for a covert force to enter Afghanistan and kill bin Laden.
Another possibility is to strike specific targets in countries that harbor terrorists. Vice President Dick Cheney said Sunday that nations which sheltered bin Ladin face "the full wrath of the United States." He identified Afghanistan as a likely target.
A delegation of senior Pakistani officials is expected to go to neighboring Afghanistan today to demand that the ruling Taliban militia hand bin Laden to the US.
For former CIA Director Stansfield Turner, war is an "ill-advised" word for the president to be using so intently, because it raises high expectations among the American public and foreigners - both ally and foe - and suggests rules and objectives that probably are not applicable in this situation.
Mr. Turner holds out hope that Bush is trying to "redefine" the word when he speakers of "the first war of the 21st century," but he says he doubts the president or anyone else could be approaching in such a sophisticated way something that a week ago was not at the forefront of national thinking. "The use of military force can only be a small part of the solution to this problem," he says.
This message appears not to have been lost on the administration. While White House spokesman Fleischer says the president is planning action that could even involve ground troops he adds that "this is not just an old-fashioned battle on a battlefield with tanks and sand."