The sun is setting in southern Germany as an elderly couple walks down a forest path. They are dressed in loden green against the crisp autumn air and carry hiking sticks on their peaceful outing.
A few hundred meters farther up the hill, however, a young man from Beaumont, Texas, is in the middle of ''World War III.'' US Army 2nd Lt. Alfred Sebile is lying on his stomach in the mud, poring over topographical maps. In a perimeter around him, the 24 soldiers in his squad are crouched behind trees, their faces camouflaged, their weapons protecting this wooded hilltop.
In an hour or so, helicopters will lift them off, and they will ''attack'' an enemy radio post in the town below. Then these young Americans from places like Amissville, Va., and Pembroke, Mass., will head back to their base near Stuttgart, tired and dirty after a 20-hour day of mock combat.
At the Pentagon these days, the talk is of forward defense, flexible response , and burden sharing, how to maintain a credible allied conventional deterrent against a Soviet military that outnumbers the West in tanks and other major equipment by 3 to 1. There have been some 40 terrorist attacks against US military property this year, most recently a bomb in southern Germany that destroyed at least 20 autos and damaged buildings. The -perennial question - Is NATO in crisis? - once again is being debated.
''I'm not afraid of the Russians,'' says Lt. Col. Dale McGarry, commander of a tank battalion here. ''They're not 10 feet tall like everybody says. I really don't worry about the (weapons) ratio, because I don't think the Russians are that proficient. . . .''
Later this day, another young US Army lieutenant colonel, Terry Gordon of Opelousas, La., echoes this feeling.
''I have a good idea of the forces opposing me, where they're likely to come from, what equipment they have, and how they're likely to use it,'' says this commander of a mechanized infantry battalion of 770 men.
''I personally think we've overrated the Russians' capability,'' adds this veteran, who served two tours in Vietnam.
Brig. Gen. Roger Price, who commands the 3,500-soldier forward brigade of the Army's First Infantry Division (''The Big Red One''), says he is relatively comfortable with the forces he leads.
''Given there's warning time to where reinforcements can work, then we can do a credible conventional defense,'' says this thick-necked veteran of Pentagon battles, who says he's glad to be back in the field.
Notwithstanding this confidence expressed by those who would fight, should the politicians so decide, there are obvious problems faced by US troops here today.
Many of the living and working facilities badly need repair. Junior enlisted soldiers must wait up to 65 weeks for base housing if they want to have their families here.
Although the number of German bars and restaurants that discriminate against black GIs has dropped to a relative handful (110 out of 210,000), many blacks (who make up 30 to 40 percent of some units) still feel unwelcome off base. Other soldiers have a hard time adjusting to their European tour.
''We're a different type of people,'' says Pfc. Rolando Morales of San Jose, Calif. ''We can't really communicate with each other.''
German officials say the recent attacks against US bases here (ranging from graffiti and tire slashings to last week's bombings) are the work of extremists who do not represent German popular opinion. Polls bear this out, and American officers agree. But they are strengthening their security efforts nonetheless.
Some commanders worry about the growing number of women in their units, of which an average 10 percent are pregnant. General Price notes that some of the 140 women in his command have difficulty changing tires on a five-ton truck, for example, even though that is part of their jobs as drivers and could be crucial in time of war.
Although the Army is recruiting the best qualified young people in peacetime history (judging by the number with high school diplomas), what officers call ''turbulence'' still occurs in units with people constantly transferring in and out. Unit cohesiveness should improve, however, with the Army's new ''cohort'' program. Here, groups of 100 or so train, ship out, and serve overseas together.
And everywhere in the NATO-based US Army, as in all of the services, one hears complaints about the lack of ammunition for training. Crews assigned to fire the TOW or Dragon antitank weapons or Redeye antiaircraft missile, for example, get no more than one training shot a year at present.
''We've got to upgrade our capabilities to keep pace,'' says Lieutenant Colonel Gordon, who otherwise is confident that the Warsaw Pact 3-to-1 edge in major weapons leaves NATO with the ability to successfully defend against any attack from the East. ''I think we could hang in there until the Henry Kissingers of the world straighten it out.''