BUCHANAN, LIBERIA -- A lithe young man wearing a silk top hat with a fluorescent red feather in the band sat in a dignified pose, cradling an AK-47 assault rifle on his knee. His head turned to follow the path of an overflowing truck that roared out of the National Milling Co. of Liberia and bumped off down a dirt road.

"Caritas," read an inscription painted on a door of the truck. "Catholic Church." But the truck carried no flour for the hungry. Some 75 combatants of the National Patriotic Front of Liberia rode in it instead, brandishing a motley collection of weapons ranging from rusting single-shots to modern M-16s outfitted with grenade launchers.

In the warm, sticky morning of coastal Liberia, where the Atlantic washes the western shore of Africa, the rebels were off to another chapter in their tragic little war.

The Catholic charity provided transport, albeit unwillingly. The National Milling Co. supplied headquarters for the commander in chief, the "C-I-C," as rebel leader Charles Taylor is referred to among his followers. And the entire port of Buchanan was under the rule-by-gun of a chaotic uprising by several thousand men and boys fighting fitfully toward the besieged capital of Monrovia with tribal revenge uppermost on their minds.

By all accounts, the war has neared its end. President Samuel K. Doe has lost control of most of the country. His army, which once numbered 5,300, has been reduced by at least half since the rebellion began Christmas Eve.

Doe has been holed up in his Monrovia palace for two weeks, negotiating the conditions of a flight into exile aboard a helicopter that is part of a standing offer from the United States to help him flee the country. Meanwhile, rebel forces have battled to the Monrovia suburbs and seized control of all the roads leading into and out of the capital.

"It's better for Doe to leave," said Christopher Selekpoth, a 20-year-old rebel at a northern way station. "Because if we have to go on in there, it's going to be so bloody. It would be terrible."

On both sides of the stalemated front line, the institutions of the country have collapsed. Liberia has become a place where youths with guns dictate the law, and a constitution proudly patterned after that of the United States has been long forgotten.

According to reports from Monrovia, Doe's soldiers have looted the city. Rebel forces, the top-hatted youth among them, have raided shops, occupied homes and institutions and confiscated vehicles throughout the rest of the country.

One result is that bright red-and-yellow running togs looted from clothing stores have become the chief sign of rank wherever Taylor's combatants gather.

Liberia's collapse into the anarchy of bush war, tragic for its people, has been embarrassing for the United States. U.S. interests here, although not essential to American well-being, are important on the African scale.

The interests include an Omega communications and navigation relay station, a Voice of America transmitter and, according to a U.S. official, a tradition of short-notice landing rights for U.S. military aircraft.

But most of all, the United States has always been regarded as Liberia's patron. The capital is named after a U.S. president, James Monroe. From 1980 to 1985, when Doe reneged on a promise to hold fair elections, Washington's aid amounted to nearly one-third of Liberia's budget, more than half a billion dollars.

"We have always had a special relationship with Liberia, and therefore a special responsibility there," said a U.S. diplomat in the region. "We would really look bad if Liberia were to go bottom-up."

How a country could go more bottom-up than Liberia was unclear in a four-day drive through rebel-controlled territory, starting at the Ivory Coast border just below the Nimba mountain range and moving south to Buchanan, on the Atlantic coast about 50 miles southeast of Monrovia.

Taylor's National Patriotic Front has armed what is left of the population, thinned considerably since tens of thousands of refugees have sought safety in neighboring Guinea and Ivory Coast. At most villages, rebels have set up checkpoints where youths with Beretta submachine guns or old shotguns man wooden gates and hassle passersby for food and cigarettes.

Opahia Kardor, who said he is 15, became one of the guards recently, after receiving rudimentary military instruction and the World War II vintage Beretta. He was assigned to an "SB Unit" -- SB for small boy -- and told to guard a former Baptist mission at Tapeta.

At the village of Wayzo, where residents said they have received only a little rice in recent days, the manager of a wooden lean-to with a few old tires gathered outside has been deputized chief of the "National Patriotic Front of Liberia Motorpool" -- with a typewritten badge to prove it.

Refugees walked along nearby roads in small groups toward the south, heading for Buchanan and what rumors said was a store of rice. To pass through the checkpoint, the hungry peasants had to show passes issued by G-2, the military intelligence and civilian administration wing of Taylor's National Patriotic Front.

Alfonso McCranada, a G-2 agent who used to be on the Monrovia police force, said rebel combatants have to be on the alert even behind their own lines because of the possibility of army ambushes.

The population -- what is left of it -- seems eager to cooperate with the rebels. People have not forgotten the massacres that took place when Doe's army rampaged through northern Liberia last January soon after rebel forces invaded from Ivory Coast.

The main road leading south is picketed at intervals with skulls upon stakes to remind them of the rampage. The civilian death toll from the army's early attempt to wipe out the rebels is uncertain, but estimates place it in the thousands.

There is also another reason for the caution of the rebel forces: the war within the war.

Prince Johnson, who entered Liberia with rebel forces in the Christmas Eve invasion, has turned against Taylor with a few dozen followers. Johnson has staked out his own territory at the Bong Mines northeast of Monrovia.

Before Taylor can increase military pressure on Doe, he must finish off Johnson. Attempts at reconciliation having failed, McCranada said, Taylor last week dispatched about 300 of his best-trained fighters, all "special commandos," to crush the revolt.

Johnson's problem with Taylor is to a great extent Taylor's problem with Doe, and Liberia's problem with itself: tribal rivalry.

In a number of conversations, rebel combatants made clear that their main motivation in following Taylor is to end and avenge what they regard as unfair domination by Doe's 4 percent minority Krahn tribe over other ethnic groups, chiefly the Gio and Mano peoples. Although Taylor has expressed repeatedly that his victory would not mean any one tribe would dominate, his rebel forces seemed clearly to define the war as an opportunity to retaliate for abuses during Doe's decade in power.

"The boys are fighting to get their vengeance," an educated rebel combatant explained.

Foreign reporters have witnessed at least one execution ordered by rebel combatants because the victim was a Krahn. A number of other Krahns have been arrested and beaten in rebel-held territory near Monrovia, they said.

Taylor, however, traces his bloodline mostly to the Liberians who ran the country for years until Doe took over in a coup d'etat in 1980 against President William R. Tolbert. Tolbert, who was executed by Doe, was a descendant of the black Americans who founded Liberia in 1822. Their descendants -- Americo-Liberians, as they are known -- became the country's power elite. Until Doe's coup, Liberia had never been ruled by any of its indigenous peoples.

So for Johnson, a Gio, Taylor's roots mean a risk that the native tribal group that forms the majority of the country's 2.4 million inhabitants might be overshadowed yet again by the Americo-Liberians.

Taylor, 42, has explained his rebellion as a drive against Doe's corruption and dictatorial rule. A former head of the Liberian General Services Administration, Taylor fled the country in 1983 after being accused by Doe of stealing $900,000.

He fled to the Boston area, where he had graduated from Bentley College in Waltham with a bachelor's degree in economics in 1977. He was arrested in 1984 at the request of Doe's government and held at the Plymouth County House of Corrections to await extradition to Liberia. But in 1985 he escaped.

Taylor, who denies he embezzled any money, has told foreign reporters that as soon as he overthrows Doe, all charges against him will be dropped.

Taylor's men said they had been told that the Natonal Patriotic Front plans to run the country for about six months after its widely expected victory, then organize elections. But Taylor has been quoted as saying, "Don't think we are going to turn the government over to someone to screw up." Elections, he has said, do not figure in his plans for at least three years, perhaps five.

The educated among the rebels freely acknowledge that the ragged bands of armed youths who make up Taylor's army will have trouble returning to normal life without the rewards for their tribes they have been led to expect.

Although Taylor has denied it, his men said that some of them have received military training in Libya, others in Burkina Faso and Ivory Coast. One rebel official said the "special commandos," numbering about 300 when the revolt began, were those who came from Libya with weapons and the fundamentals of rebel warfare.