Peace negotiations are hopelessly deadlocked after a six-hour meeting between North Vietnamese negotiator Le Duc Tho and National Security Advisor Henry Kissinger. After the meeting, Kissinger flew to the United States to confer with President Richard Nixon.
The main point of contention was who would have political power in South Vietnam if a cease-fire were announced. The North Vietnamese negotiators demanded the following in the case of a cease-fire: the dissolution of the government of South Vietnamese President Nguyen Van Thieu, the disbanding of the South Vietnamese army, and the installation of a coalition government. The U.S. refused to consider the North Vietnamese demands and steadfastly supported Thieu and his government.
At the same time, the South Vietnamese were making their own demands. Over 100,000 North Vietnamese troops had occupied territory in South Vietnam during the 1972 Easter Offensive. Nguyen Van Thieu demanded that the North Vietnamese recognize Saigon's sovereignty over South Vietnam, which would make the continued presence of the North Vietnamese troops in the south illegal. The North Vietnamese refused Thieu's demands, saying that they would not recognize Thieu's government and would not remove their troops. They walked out of the negotiations.
Nixon issued an ultimatum to Hanoi to send its representatives back to the conference table within 72 hours "or else." When the North Vietnamese rejected Nixon's demand on December 18, the president gave the order to launch Operation Linebacker II, an intensified bombing campaign of North Vietnam that became known as the "Christmas bombing." Over the next 11 days--with the exception of Christmas Day--the bombing continued unabated, with an estimated 20,000 tons of bombs dropped over North Vietnam. On December 28, North Vietnamese officials agreed to Nixon's conditions for reopening the negotiations; the next day, the president called an end to Linebacker II.