He was a member of the anti-Vietnam War group Beheiren.

Entity and relation annotations:
id: 0
type: entity
value: text: Beheiren
labels: <Organization>
id: 1
type: entity
value: text: Vietnam War
labels: <Event>
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type: entity
value: text: member
labels: <Title>
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to_id: 2
labels: Organization:Establishes:Title
from_id: 0