Paul Bucha, a Medal of Honor recipient who saved fellow American soldiers from slaughter during the Vietnam War and who in later years became both a public endorser and a critic of presidential candidates, died on July 31 in West Haven, Conn. He was 80.

The death, at a veterans’ hospital, was caused by complications of Alzheimer’s disease, his daughter Heather Whaley said.

In 1965, Mr. Bucha (pronounced BYU-kah) graduated from West Point in the top 5 percent of his class and as an All-American swimmer. Two years later he was sent to Vietnam as an Army captain.

He was soon appointed commander of the last rifle company to be formed during an Army expansion — one that left him with a collection of the least coveted recruits: men who had flunked basic infantry tasks, former prisoners and “guys with master’s degrees in Elizabethan literature,” Mr. Bucha later recalled to the National Purple Heart Honor Mission, a veterans group.

The bloody Tet offensive of 1968 began soon afterward, and his unit was charged with helping to repel the attack by North Vietnamese and Viet Cong forces. By March, the group was down from 164 men to 89.