WASHINGTON -- Humbled by America's bloody experience in Iraq and Afghanistan, the U.S. military is looking ahead with rising concern to a decade of widening terrorism and insurgency, new conflicts in overcrowded, failing states, and the near certainty that additional nations or terrorist or criminal gangs will obtain nuclear weapons.
The United States is less prepared to meet these problems than at any time in the past decade, according to senior U.S. strategists and outside analysts.
Its military, built for a bygone era of high-speed, high-tech attack and massed firepower, is exhausted and acknowledges that it cannot defeat insurgencies without help. And its civilian agencies are poorly organized to help stabilize failing states with commercial and developmental help or even to creatively promote American values abroad, senior officials said. Restructuring them will be a long and difficult process that one official compares to "changing a tire at 60 mph."
For today's presidential candidates and the war-weary public, this dismal kaleidoscope of problems is not good news - even if today's wars remain manageable. It suggests an era ahead in which the United States will find its ability to take the strong, unilateral action befitting the world's only remaining superpower increasingly out of reach.
"The best we can do with all these problems is just coping," said a senior strategic planner who spoke on condition of anonymity. "What the United States cannot do any longer is strategy by assertion."
Experts such as Marine Lt. Gen. James Amos are starting to call this new era one of "hybrid war," a term they use to describe an unpleasant mix of security problems already festering across a broad swath from Columbia to the Congo and across the Middle East to Southeast Asia.
It is not what President Bush has called the global war on terror. This runs deeper and broader.
As in Iraq - and Darfur, and Gaza - there are no front lines in hybrid war, nor clear distinctions between civilian and fighter.
Rather than the announced commencement of hostilities, violence in hybrid war erupts unpredictably from dormant tension and subsides only to break out elsewhere in a more virulent form. It is tricky to forecast, perilous in which to intervene.
The one certainty when American troops move out to confront these dangers is that "the moment you step off across the line you will be surprised," Marine Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, said in an interview.
Increasingly, governments across this region are unable to cope with a swelling youth population demanding education and jobs. Sixty million Pakistanis are under age 15, in a population that has doubled in the past 30 years and will double again by 2025. A third of them live below Pakistan's poverty line.
Combining the frustrations of overcrowding and poverty with radical sectarian politics is a classic recipe for violent conflict, as Pakistan and many other regions are experiencing.
Amos, charged with thinking about how the Marine Corps should be organized and trained for the future, expects a series of messy half-wars that will include conflict over scarce resources.
"People will fight over oil and water, and not necessarily in that order," he said.
Where there is wealth, it has brought trouble. Analysts cite oil-rich coastal Nigeria, where petrodollars have spawned official corruption and organized crime against a backdrop of grinding poverty. Not surprisingly, piracy and terrorism are rampant there.
Americans have been surprised at the depth of hatred and depravity that can drive these frustrations into violence. Army Lt. Gen. Ray Odierno, just finishing a 15-month tour in Iraq, cites the case of two Iraqi women, who he believed had Down syndrome, who were strapped with suicide bombs and sent into crowded Baghdad markets last month.
Suicide bombings were virtually unknown in Afghanistan until three years after the U.S. intervention, then jumped more than sevenfold from 2005 to 2006 and are still rising, according to the U.S. command in Afghanistan.
Such methods are deadly and effective, finding gaps in America's trillion-dollar defenses and driving the Pentagon to even more costly and cumbersome responses. Modifying the electronics in cheap homemade bombs "with a dollar's worth of parts from Radio Shack," as a senior Pentagon official put it, Iraqi insurgents forced the Defense Department to order $16 billion worth of heavy armored vehicles.
Hezbollah insurgents in Lebanon used armed drone aircraft and sea-skimming anti-ship missiles in its war with Israel. Most officials and analysts believe it is only a matter of time before such a group has or claims to have a nuclear weapon.
A nuclear blast would wreak havoc with deployed U.S. forces, according to senior officials. Ports and airfields where troops congregate are unprotected. So are major assets like aircraft carriers, with crews of about 6,000.
Yet one four-star officer added: "I am probably more worried in the near future about bio," a reference to a possible attack on the United States with biological weapons. The potential for death and chaos "is staggering," the officer said.
All this means scant rest for the military, which has carried most of the burden of Iraq and Afghanistan. Those conflicts will continue, most analysts say, stretching the military even as the Army and Marines grow by more than 100,000 troops. Operational plans for the Army and Marines call for more foreign involvement ahead, not less.
The United States "has no choice but to get involved," said retired Army Maj. Gen. Robert H. Scales, a strategist and historian. "The enemy is the one who has the strategic initiative, picking the places to fight, in the most inhospitable parts of the world. Scales said U.S. adversaries will attempt to draw Americans into kill zones as they have in Iraq.
"We anticipate Marines being more forward-deployed, post-Iraq," Amos said in an interview.
Because of the military's limitations and the nature of hybrid war, many see a growing requirement for the U.S. government to focus its economic, diplomatic, cultural and moral power abroad.
Inside the Pentagon, this is often referred to as a WOG approach, for "whole of government." It could be used to build and fortify a local economy and civilian police force before conflict breaks out.
In Iraq and Afghanistan, most of that burden lies with the military, which has responded in limited but creative ways. Paratroopers have trained police, and the Missouri National Guard has sent 50 experts in agribusiness to Afghanistan to help give farmers a lucrative alternative to growing poppies.
But what if the United States had been able, six years ago, to dispatch hundreds of these experts along with road builders, teachers, and people who could train police, judges and local administrators?
As critics such as Defense Secretary Robert M. Gates observe, U.S. national security bureaucracies at the CIA, State Department and National Security Council were designed six decades ago at the outset of the Cold War. For today's conflicts, they are dysfunctional.
In a speech last fall, Gates said new civilian institutions are urgently needed for the new era of conflict in which success will be "less a matter of imposing one's will and more a function of shaping behavior - of friends, adversaries and, most importantly, the people in between."
Building that capacity "will require a strategic reassessment of how the U.S. government is organized, coordinated and budgeted," said a recent study by the Center for Strategic and International Studies, in Washington.
"America must retain its military superiority, but in today's context there are limits" to what the military can achieve on its own, CSIS said. "The key is not how many enemies the United States kills, but how many allies it grows."
But military leaders know that capability is still distant.
"The government is not organized for the world we're living in," Mullen said recently. "Until it is, the military will be carrying a lot of the burden."