 By the time Westmoreland became army commander in South Vietnam, the option of a Korea-type settlement with a large demilitarised zone separating north and south, favored by military and diplomatic figures, had been rejected by the US government, whose objectives were to achieve a decisive victory, and not to use vastly greater resources.The infiltration by regular North Vietnam forces into the South could not be dealt with by aggressive action against the northern state because intervention by China was something the US government was concerned to avoid, but President Lyndon B. Johnson had given commitments to uphold South Vietnam against communist North Vietnam.Chief of Staff of the United States Army, General Harold Keith Johnson, and subsequently historians such as Harry G. Summers, Jr. came to see US goals as having become mutually inconsistent, because defeating the Communists would require declaring a national emergency and fully mobilising the resources of the US.