 To assist the South Vietnamese who proved incapable of taking the town of Tchepone, Laird approved of the largest helicopter assault of the entire Vietnam war.On 6 March 1971, 276 American helicopters took two battalions of South Vietnamese infantry into Laos.Unlike the invasion of Cambodia the previous year, the invasion of Laos caused few protests in the United States mostly because Lam Son was perceived as a South Vietnamese operation, not an American one, which for Laird was a sign of the success of Vietnamization.