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In his early Senate years he was seen as a " prairie populist " , working on legislation protecting farmers ' prices and also on compensating veterans sickened by Agent Orange defoliant spraying in the Vietnam War .
 Vietnam War, Agent Orange, Senate
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, else, organization, person 
Text: {0} 
Answer:
 Vietnam War, Agent Orange, Senate