Decenber 16, 2004 - Griping among the troops is as old as armed conflict, illustrated most memorably by cartoonist Bill Mauldin's "Willie and Joe" characters during World War II. But something more than that is happening now in Iraq with what appears to be growing resistance from the troops.

Evidence includes numbers of deserters (reportedly in the thousands), resignations of reserve officers, lawsuits by those whose duty period has been involuntarily extended, and a refusal to go on dangerous missions without proper equipment. There's also been a willingness at grunt level to publicly challenge the Pentagon - as Defense Secretary Donald Rumsfeld found out recently in a trip to the war zone, where he got an earful about unarmored humvees.

While some don't see much defiance - and, in fact, have been surprised by the depth of solidarity - others see an unusual amount of tension surfacing for an all-volunteer military force.

"What is driving the resistance is the same thing that drove it during Vietnam - a lack of trust in the civilian leadership and a sense that the uniformed leaders are not standing up for the forces," says retired Army Col. Dan Smith, a military analyst with the Friends Committee on National Legislation in Washington. Colonel Smith doesn't expect the kind of "fragging" incidents that occurred in Vietnam where soldiers attacked their own officers. "This force is too professional," he says. "But the lack of trust and the inequity of the tours will very likely be reflected in the numbers of Guard and reservists who vote no-confidence with their feet."

That already appears to be happening. The Army National Guard is short 5,000 new citizen-soldiers.

"Although generally successful in overall mission numbers, we continue to experience difficulty in attracting and retaining qualified individuals in certain critical wartime specialties," Army Reserve chief Lt. Gen. James Helmly told the House Armed Services Committee earlier this year.

The number of officers wanting to resign from the Army Reserve has jumped as well. And according to a recent report on CBS's "60 Minutes," the Defense Department acknowledges that more than 5,500 service personnel have deserted since the Iraq war began.

While the complaints and the resistance to following some military policies may pattern earlier conflicts, the fighting in Iraq has a unique context, experts say.

It's the first large-scale 21st-century conflict against an aggressive insurgency, causing thousands of US casualties; the first war in more than a generation in which homeland security and the threat of domestic terror attack seem so real; the first "semi-draft," with the Guard/reserve component approaching 50 percent of combat and combat support troops (and already taking more casualties than they did in Vietnam); and it's the first time in many years that soldiers have been ordered to serve beyond their commitments.

Legal challenges to military authority appear to be increasing as well, with more use of civilian attorneys than was seen in Vietnam. "It's very much in evidence," says Eugene Fidell, a former military lawyer who heads the National Institute of Military Justice. Mr. Fidell just finished teaching the first course on military issues at Harvard Law School since 1970.

All this is happening in an age when CNN brings live war coverage to the trenches and barracks, when troops are more aware of the successes and debacles on the battlefield than ever before. At the same time, reporters embedded with combat units, as well as e-mail and Internet access, make it easier for families and others back home to be heard by the soldiers - and for the soldiers to complain to them. This is especially true, perhaps, of citizen-soldiers, who are not only older than the average GI but more used to speaking out.

Since the fighting began in Iraq, the number of Guard and reserve troops on active duty has more than doubled. Critics say this is an indication that US forces are stretched too thin. One such critic is Senator John McCain (R) of Arizona, a supporter of the war who declared this week that he had "no confidence" in Secretary Rumsfeld.

At this point, much of the data is scattered and anecdotal, like the doubling of desertions at the Army's Fort Bragg in North Carolina last year to about 200. It may be too early to draw exact comparisons with earlier wars, experts agree.

But they also note a growing trend for GIs to speak out and to find leverage points to protect their interests - including personal safety. "I am amazed that it is not greater," says retired Air Force Col. Sam Gardiner. "The war continues to go badly. Their equipment is in bad shape. Supply problems continue. Tours are extended. Many are on a second or third deployment to a combat zone. I would expect a louder voice."

A key issue for war planners is whether any of this adversely effects individual morale and unit performance. That remains an open question, particularly as the war goes on and its original rationale (weapons of mass destruction and ties to Al Qaeda) fades.

"Soldiers always gripe, and often with good reason," says Loren Thompson, head of security studies at the Lexington Institute in Arlington, Va. "But I don't see much evidence that the enemy in Iraq is eroding the will of US forces to fight. As long as US forces are well led, the gripes aren't likely to lead to more serious problems."

Others aren't so sure.

"When you are risking your life on the battlefield, the importance of knowing why you are doing so cannot be underestimated," says Ivan Eland, national security analyst at the Independent Institute in Oakland, Calif. "If soldiers don't know why they are fighting there or believe they've been hoodwinked, we may see the same phenomenon happen in Iraq as occurred in Vietnam."