For much of the past decade, American national security has been driven by one overriding doctrine: The US must be able to win two major wars waged at the same time.
That strategy, outlined in 1993, has been a guide for defense spending, troop deployment, and in some cases international diplomacy.
But, analysts say, it is an approach whose time may have run out.
With the emergence of new threats - and forecasts for mushrooming defense budgets - most military experts say that the Pentagon needs to develop a new strategy for the 21st century.
"If we don't think through the future problems that our adversaries can throw at us, then we'll have the worst of both worlds," says Andrew Krepinevic, the director of the Center for Strategic and Budgetary Assessments in Washington. "We'll pay for expensive weapons systems, and our security will be jeopardized."
One of the new threats facing the US was foreshadowed last week, when computer hackers attacked commercial Web sites, shutting them down for hours. Other concerns range from biological and chemical weapons to long-range missile attacks from rogue nations.
Additionally, soldiers and weapons are more vulnerable than ever when deployed to fight a regional war. They can be located with readily available satellite technology, and, once found, can be hit.
These concerns signal an emerging ability of small, hostile countries to reach the US through nonconventional methods.
At the same time, the threats envisioned in 1993 have diminished or changed form. It is becoming less and less likely that the US will have to fight a war in which it relies on a large number of ground troops and heavy equipment.
One anticipated "major-theater war" was a repeat of the Persian Gulf war. But Iraq's forces have been significantly depleted since then, and analysts say the US would no longer need a Desert Storm-size contingency to defeat Saddam Hussein.
The second threat was a war in Korea. Yet since the beginning of the Clinton presidency, North Korea's economy has collapsed, and it has focused its few remaining resources on building missiles - not conventional ground forces that require a US buildup. In addition, South Korea, North Korea's primary rival and a US ally, has gotten stronger.
"In recent years the [two major-theater wars] framework has sufficed," concludes the most recent strategic assessment from the National Defense University in Washington, "but something broader and more responsive may be needed in the future."
According to Kim Holmes, a national-security expert at the Heritage Foundation here, the US military is so underfunded and overextended that even the two-war capability may not be realistic.
"We cannot do two wars simultaneously," he says. "It's more like 1-1/2 wars right now."
Some analysts say the US should prepare to fight one major war and two minor interventions simultaneously. This would take into account the new tendency to deploy peacekeeping troops in far away places, such as in Kosovo and Africa.
Another possibility is that America concentrate predominately on so-called "homeland threats" against itself - not international peacekeeping - and devise a strategy to defend against these threats.
But one of the difficulties of changing defense strategy, analysts say, is the slow process of developing and producing weapons. After sizable preliminary investments, projects become difficult to stop, and a change of military planning could turn the whole process on its head.
For example, the Pentagon is currently undergoing expensive equipment modernization in each of its forces - including new aircraft, upgraded tanks, and a new heavy-artillery system. By 2006 and 2007, costs will skyrocket as these programs go into full-scale production, warned Defense Secretary William Cohen in a Senate committee meeting this month.
Analysts estimate that maintaining current force levels and undergoing the proposed modernization will eventually require a $30 to $50 billion defense-spending increase from current levels.
President Clinton requested $305.4 billion for the Pentagon in the 2001 budget.
The Pentagon is also trying another expensive task - transforming its forces into smaller, lighter fighting units.
Being able to fight two major wars at the same time is a luxury the Department of Defense cannot afford, says Michael O'Hanlon, a researcher at the Brookings Institution in Washington.
"Do we really need such a conservative way of thinking about regional conflict?" he asks. "This hamstrings the Pentagon. It hurts them in research and development and readiness."
Nevertheless, a change in military doctrine is unlikely in the immediate future, analysts say.
Clinton has been unable to reshape the military because he does not have a strong-enough standing in the defense community - something that would certainly be needed for such a radical change.
Meanwhile, the four major presidential candidates have shown limited interest in defense. By virtue of being Democrats, Vice President Al Gore and former Sen. Bill Bradley may face some of the same stigmas of being weak on defense issues that were encountered by Clinton.
Much of the Pentagon's upper brass is Republican.
Texas Gov. George W. Bush, meanwhile, has been criticized for lacking specific knowledge about defense. And even Sen. John McCain, a former Navy pilot and prisoner of war, has been vague on military issues.
"It's the same old story," says Mr. Holmes of the Heritage Foundation. "Nobody cares about [national security] until there's a disaster."
(c) Copyright 2000. The Christian Science Publishing Society