GEORGE S. McGOVERN is, in some sense, the reason I exist. My parents met as radical community organizers in their early 20s, an idealistic honey-haired student at the University of California, Santa Cruz, and a scraggly wannabe farm boy from Brown University, knocking on doors for the now defunct Acorn.

It’s a typical 1975 story, except that they were pounding the pavement in Sioux Falls, S.D., a provincial little city at the edge of the upper Midwest and the Great Plains. Stranger still, they stayed in the state — my dad for nearly 40 years, my mom for 15.

It’s astonishing to think now, but South Dakota made sense as a destination for idealistic young liberals in the mid-1970s. Senator McGovern, who died Sunday at the age of 90, had run an inspiring but catastrophic campaign for the presidency three years earlier, bravely opposing the Vietnam War. The state’s junior senator, James Abourezk, was another liberal Democrat and the first Arab-American elected to the upper chamber. And Red Power activism was roiling the state’s Indian reservations; the Wounded Knee standoff on the Pine Ridge Reservation even captured the nation’s attention for several months in 1973....

We found a place amid a Plains liberalism whose patron saint was Mr. McGovern: Christian, populist, antiwar. Mr. McGovern, the son of a Methodist minister, had become horrified with war as a bomber pilot in World War II and studied theology when he returned home....