CANTON, S.D., JULY 31 -- In a sweltering high school gym, where he had come to discuss his farm policies today, Vice President Bush found himself offering carefully worded condolences to a young man whose brother was killed during a contra ambush while working as a volunteer in rural Nicaragua.

Taking questions at a packed town meeting in rural southeastern South Dakota, Bush was confronted by John Linder, whose brother, Benjamin, was slain by Nicaraguan contras last April.

Linder challenged Bush to condemn his brother's killing, saying, "Nobody has said it is terror. Nobody has said it is murder. Nobody from your administration has said this is a wrongful death."

The vice president offered a lengthy reply that touched on his own wartime experience and his witnessing the deaths of fellow soldiers. He emphasized that he knew how painful the death had been for Linder's family.

"I know the agony, having been in a war and having fought for my country," Bush said. "It is tough. It is ghastly. For a family, it is just horrible. . . . "

But, Bush said, Benjamin Linder made a conscious choice to work on the opposite side of his nation's allies.

"Your brother, I am sure out of conviction, was supporting the Marxist-Leninists -- or maybe, I'll give you the benefit of the doubt, maybe he was just trying to help people in the rural countryside.

"So, he made his choice. Of course, I mourn the death of every American, of everybody," Bush said.

Bush's reply brought hearty applause from the audience.

Linder, however, shook his head frequently while the vice president spoke. And he disagreed vigorously at one point, when Bush said that according to some accounts, Linder's brother was carrying a Soviet-made rifle -- an AK47 -- and owned Sandinista uniforms at the time he was killed.