That was the central theme of a much-anticipated Pentagon strategy report prepared for Congress every four years and released yesterday.
The 71-page report, known as the Quadrennial Defense Review, was begun in June and substantially written before the Sept. 11 terrorist attacks on the World Trade Center and the Pentagon, but defense officials said those events intensified the emphasis on combating terrorist attacks.
A senior defense official told reporters that even before the attacks, officials had concluded that terrorism, chemical and biological weapons, cyberattacks and missile threats "would transform the landscape in which we live."
But the official said that it was too soon to determine how the Pentagon would restructure itself and train its forces to battle terrorism at home.
"That will be a task that will be in large part taken up by the Guard and the Reserve," said the official.
The Office of Homeland Security created by President Bush in the aftermath of the attacks will take the lead in coordinating a national strategy, said the report, while the Pentagon will set up a task force to determine what roles and missions the military can perform - and how much it will cost.
The report said it was "clear" that military forces, including the Coast Guard, need more money, equipment and perhaps different organizational structures to meet the terrorist threat at home. And it said a new military command might be needed to oversee the homeland defense.
Said one military officer involved in compiling the report, "We're not prepared for homeland security."
As a first step, the Defense Department will place a "new emphasis" on counterterrorism training for federal, state and local fire, police and rescue officials, the so-called "first responders" to a terrorist attack, said the report. Guard and Reserve personnel already are handling such training.
The official acknowledged that the Guard and Reserve are "busy everywhere," including on peacekeeping missions, such as in Bosnia, where the 29th Infantry Division, made up of citizen soldiers from Maryland and other states, deployed last month.
During the summer, there was an expectation that the Pentagon report would call for cuts in troop strength to help pay for missile defense and more sophisticated intelligence equipment, such as satellites and sensors. Trimming the eight National Guard divisions to four was one of the cuts contemplated.
But the official said yesterday that Pentagon leaders concluded before the attack that the force level should probably remain stable. There are 1.4 million men and women on active duty and 1.3 million in the Guard and Reserve.
Michael E. O'Hanlon, a defense analyst at the Brookings Institution, said the report was "skeletal in detail but in the right direction" on homeland defense. Still, he said, the report did not call for any cutbacks in current weapons systems or in the overall troop strength of the armed forces to help pay for the renewed terrorist effort and the modernized military that Defense Secretary Donald H. Rumsfeld has said is needed.
For example, the Pentagon wants to build three types of fighter jets totaling about 3,700 planes, as well as a long-range artillery system originally designed to fight the now-defunct Soviet Union, O'Hanlon said. The Pentagon, he added, may get more money in the short term but perhaps not enough to pay for all its weapons systems.
The report "contains no tough choices," he said. "It's not a planning document; it's more a long-winded, badly written speech."
O'Hanlon's views are reflective of other military analysts, including some in the Pentagon. Even before the terrorist attacks, they questioned how the Defense Department would finance modernization without cutbacks in weapons systems or personnel.
Meanwhile, the report said that the Pentagon should place more focus on Asia as a region for possible conflict and defense of U.S. interests. And the military must put a greater emphasis on high-tech intelligence systems and weapons - such as remote sensors and long-range precision missiles - and troops that can be dispatched overseas quickly.
As a result, the Pentagon has decided to accelerate the Army's push toward creating a brigade-sized force with lighter weaponry that can deploy anywhere within four days, according to the report. The report calls for one such brigade to be stationed in Europe by 2007. The Army also will look to beefing up its ground strength in the Persian Gulf region.
The Navy will increase aircraft carrier presence in the Western Pacific, as well as putting more ships and submarines in that area, the report said. And the Air Force will look to increasing its aircraft in the Pacific and Indian oceans as well as the Persian Gulf.
Finally, the Marines will look at shifting some of their pre-positioned equipment in the Mediterranean toward the Indian Ocean and the Arabian Gulf so they can be more responsive to missions in the Middle East, according to the report. Officials also will try to come up with new high-speed sealift and amphibious capabilities for the Marine Corps.