IN NORTHEASTERN SAUDI ARABIA -- Not many months ago they staged evening parades, saluted world leaders on the White House lawn and occasionally got a pat on their ramrod straight backs from President Bush for ceremonies crisply executed.

"We're the postcard image of the U.S. Marines for the rest of the world," said Staff Sgt. Don Smith, of the "8th and I," a Marine unit that had not been called into battle in generations.

On Jan. 1, about one-third of the 1,000-strong, District-based outfit arrived in Saudi Arabia, leaving behind the dress blue uniforms, the spit-and-polish regulations and bland ammunition for grimy foxholes and prospects of real combat.

Here the "8th and I," named for its location on Eighth Street SE, is protecting a key unit of the 2nd Marine Division. Along a 1,500-meter front, with the featureless desert rolling out ahead until it meets the horizon, the parade-ground soldiers live two to a foxhole, manning machine guns, rockets and grenade launchers.

Cold rain has soaked them days at a time, and hot showers have come only twice since they arrived in Saudi Arabia. A constant film of sand covers skin and rumpled camouflage uniforms.

Back at their home barracks, uniforms were pressed every time they were put on, and then inspected three times a day for the slightest blemish.

Infractions that detracted from the ideal Marine image were punished by push-ups or "extra military instruction."

"If my men showed up for muster in D.C. the way they look now, well, I'd put them on the first plane to Saudi Arabia," said Smith, 29, of Burtonsville.

In fact, Smith said, virtually everyone in the unit had volunteered to serve in Saudi Arabia, and those left behind were "biting at the bit to come out here."

In Washington, the unit performs thousands of ceremonies each year at the White House, Defense Department, Arlington National Cemetery and other sites.

Ranks normally are filled by carefully selected graduates of basic Marine training, with criteria including a minimum height of 5 feet, 10 inches; high marks in general conduct and a knack for moving body parts and rifles in precise concert with others.

But following the core Marine principle that every member of the service remains an infantryman, the "8th and I" -- from trombonists to rifle-twirlers -- get trained and retrained for combat.

The outfit has stayed out of recent conflicts, but its battlefield debut dates to the War of 1812. In 1864, a detachment marched up Eighth Street for duty in the Civil War, and others fought against the Seminole Indians in Florida and the Spanish in Cuba.

"A lot of people don't consider us full-fleet Marines," said Lance Cpl. Timothy Shane Pierce, of Evansville, Ind. "But we can do the job. The discipline in our unit is actually a lot tougher than in some others.

"Although things are getting tenser with ground combat coming up, it was more relaxed than being in the barracks when we first got here," the 19-year-old Marine said, standing by a 50-caliber machine gun.

"When I get back I'll move my kids' sandbox into the house so I can feel at home," quipped Smith, sipping lukewarm coffee and hunched inside a foxhole draped with camouflaged netting.

"You get soaked by rain three days in a row and start to wonder about being here. Then you think about the job we're doing, and you wouldn't want to be anywhere else," said the 12-year Marine.

Smith described the parades on summer evenings when tourists and VIPs ringed the unit's traditional parade ground, and the last big ceremony in which he took part.

It was a burial with full honors for a retired Marine colonel who had fought on Iwo Jima, the Pacific island Marines stormed in one of World War II's bloodiest battles.

There were four platoons of 28 men plus a color guard. Six bearers carried the flag-draped coffin. Last taps sounded and a volley of 21 rifle shots was fired over the grave.

It's one ceremony the "8th and I" hopes it will not have to perform for fallen comrades-in-arms in Saudi Arabia.