In a town where speeches sprout like weeds and politics is the untended lawn, Arn Chorn, a 21-year-old Cambodian refugee, stirred an audience here as few orators ever have. On Dec. 10 at Washington Cathedral, with its wide nave and flying clerestories, Chorn spoke for 20 minutes, including two when emotion overcame him and he stopped to weep.

One thousand people, assembled by Amnesty International, had come to help Chorn and other speakers observe Human Rights Day. Chorn, a Brown University student, was among the first Cambodian orphans allowed to enter the United States. He spoke at the same hour Mikhail Gorbachev was holding a press conference a half-mile south at the Soviet compound and Ronald Reagan, three miles away at the White House, was preparing an address to the nation.

The world leaders spoke of war and peace. Chorn, a child of 9 when his family was killed in the mass slaughtering that began under the Khmer Rouge in 1975, spoke of war and survival. "I lived through the terror of seeing students disemboweled and their kidneys eaten while they were still alive ... Life, one human life, meant nothing. They even played games with the dead. Sometimes after killing, they would prop up the person as if he were still alive. I remember one man who was dead and sat looking at me. They put a cigarette in his mouth and an American helmet on his head and they laughed."

These details -- gory details, as they are called -- were in the early part of Chorn's speech. They were a necessary preface to the political opinions he offered. In 1979, when the Vietnamese invaded Cambodia, Chorn was "forced by the Khmer Rouge, the very people who killed my family, to carry guns, like thousands of other kids, to fight against the Vietnamese. We were always being forced to be in the front lines to draw fire and to die first and sometimes we children shot and killed each other with guns that were made in Russia, China and America. I think that one of the most serious human-rights violations is to allow this to happen, to allow children to carry guns to fight and die."

In 1979, Chorn was in a Thai refugee hospital weighing 75 pounds. He was befriended by Peter Pond, an American doing development work on a Ford Foundation grant. He invited Chorn to come to the United States. Pond and his wife, who live near the White Mountains in Jefferson, N.H., eventually adopted Chorn, along with 12 other Cambodian orphans. At Brown this semester, Chorn, now a U.S. citizen, is taking courses in English, anthropology, philosophy, and war and peace.

At Washington Cathedral, where many in the audience were college and high school students who had recently joined their campus Amnesty chapters, Chorn went back a few years before the Vietnamese invasion. The Americans, he said, "dropped three times more bombs on my country than in Japan during World War II." He admitted to being puzzled by this: "I am very fortunate and I am very happy that I have reached the United States, the original land of human rights ... {but} we should not ignore that even we have violated and are violating human rights ourselves. Sometimes when there is a fight in other countries between two opponents, instead of trying to help them we sell guns to both sides so they can kill each other and we make a profit out of it."

Chorn appeared to realize that his political statements might be dismissed by the sophisticated as the emotional ramblings of a schoolboy. So he spoke to that objection: "Is it childish or foolish for me to hope that peace will come? I am here to tell the world to stop shooting each other, to stop arguing ... Could there ever be Amnesty International or the United Nations to intervene in a country for the sake of the suffering people of that country? Could Amnesty or the United Nations maintain an office in every country of the world to monitor human rights? Of course, I am young and I do not know whether there is any way for this to happen. I only know that the world seems strange and silent, or slow to move, when Jews were the victims of the Holocaust and when my people were murdered."

After services at the cathedral, where his speech received a standing ovation, Chorn went to a reception nearby at the home of the Canadian ambassador. In a corner room away from milling guests, he relaxed. His large brown eyes shone with laughter as he told stories about college life at Brown.

Chorn said he had to leave early the next morning to be back to study for an exam for his war and peace course. An admirer told him to skip the exam: "You've experienced enough to be teaching the course yourself. Give the professor an exam -- on war and peace in Cambodia." "Hey," said Chorn, "what a great idea. Wait till I tell my roommate."