The American war against terrorists and their supporters in Afghanistan may be winding down as the enemy scatters and international peacekeepers move to oversee an interim government there.
Throughout, the US military seems to have worked efficiently, relentlessly, and with a controlled ferocity that illustrates its role as the sword and shield of the 21st century's only superpower. And in Washington, the ascendancy of Defense Secretary Donald Rumsfeld within the Bush administration raises the Pentagon's political clout.
But the war on terrorism also brings added urgency to a long-running debate over if, and how, the US should transform its defense policies in light of 21st-century threats.
At stake are fundamental issues:
The shape of the forces themselves. Should they be significantly lighter and more mobile, or does this war prove the worth of heavy (and expensive) aircraft-carrier battle groups, big bombers, and other traditional ways of deploying force?
The difficulties and complexities of fighting "asymmetrical war," where intelligence-gathering, multinational cooperation, international finance, the controversial notion of "nation-building," and other nonmilitary elements are increasingly important.
The challenges of maintaining public support for potentially dangerous and expensive conflicts of this type, absent direct attacks on the homeland.
In his final briefing of 2001, Secretary Rumsfeld emphasized the need to rethink US national-security policies.
Today, "it is less clear [than in the past] exactly what countries or people might pose a threat to us," he said. As a result, the US can instead define its own vulnerabilities, rather than tackling the much harder task of identifying each and every potential enemy.
This outlook, Rumsfeld said, "has really turned the strategy issue around in a distinctly different way, which will have a significant effect on how this department functions, how we manage our affairs, how we think about things...."
To what extent have the US military services (and the politicians who fund them) responded to this new era in which the main threat seems to be international terrorism? It's a mixed picture, according to most defense experts.
While big-ticket weapons - ships, tanks, and planes - often get the most attention, such hardware may be far less important than how the services are organized, given the advances in intelligence-gathering and dissemination.
"The immense powers of information technology are doing to the military what they have already done in the private sector - eliminated unneeded levels of control, flattening out the hierarchy. and increasing efficiency," says a former Army officer.
Because of advances in computer and communications technology, special-operations teams in Afghanistan - led by master sergeants, captains, and majors - have been able to perform the tasks that used to require generals and large supporting staffs, says this source, who has considerable experience in Afghanistan.
Others put it more bluntly.
"The military command structure is hugely bloated," says Larry Seaquist, a retired US Navy warship captain and Pentagon strategist. "Cutting excess [military] bases is a minor problem compared to the need to cut excess fat out of the military command structure."
And for all the post-Vietnam talk about the need for politicians to step aside and "let the generals run the war," this may no longer be possible.
"The fact is that this war is run from Washington," says Mr. Seaquist. "These kinds of conflicts are so tightly intertwined with international diplomacy, domestic politics, the media campaign, and the many other agencies also engaged - Treasury, Justice, et al. - that only the White House can manage them."
Tightly intertwined, too, are the elements of the "iron triangle" - Defense Department bureaucracies, military contractors, and those in Congress who promote them - that tend to resist change.
Rumsfeld hinted at this the other day when he said, "It's not fair to the taxpayers to continue to have something like a 20 to 25 percent larger base structure than we need."
Military contractors, however, are likely to resist changes they perceive as harming their bottom lines.
"Industry will be fighting to retain big-ticket items.... Their solution is, 'more of what we are buying now plus all the new systems,' " says Daniel Smith, a retired Army colonel and chief of research with the Center for Defense Information in Washington.
Even with the 'war' on terrorism, Smith points out, there is only so much money that can go to the Pentagon.
Still, fundamental changes of the type sketched out by US forces in Afghanistan (particularly Special Operations Forces combined with highly accurate airborne munitions) are likely to dominate the future of war-fighting, says Stansfield Turner, retired Navy admiral and former director of the Central Intelligence Agency.
These changes include: weapons that are increasingly precise thanks to satellite-using pilotless drone aircraft and global positioning systems, plus new types of warheads that are more lethal.
The flow of information from such high-tech equipment - available not only to the US but also to potential adversaries - makes forces "more vulnerable," Mr. Turner says. "Small size and greater mobility will be necessary to survive."
The need for "a revolution in military affairs" has been talked about for years, but the attacks of Sept. 11 have accelerated the discussion.
World events, however, may dictate a more evolutionary approach to the military's transformation.
"The post-Sept. 11 world may have added certain missions to our national-security agenda, but it hasn't taken any away," says Michael O'Hanlon, a defense specialist at the Brookings Institution in Washington. "Even the war on terrorism could lead to a traditional sort of war against [Iraqi President] Saddam Hussein. Regardless of that possibility, problems in Korea, the Taiwan Strait, and Persian Gulf remain that could threaten our interests and necessitate major combat operations."
In the end, says Dr. O'Hanlon, "the case for 'transformation' is real, but so is the case for continuity - meaning that, given resource constraints and technology constraints, transformation should be thought of more as a gradual process than a quick event."