The president appointed a task force, under the direction of Secretary of Defense Clark Clifford, to evaluate a request for 206,000 troops. The president's final instructions to Clifford were "give me the lesser of evils." For weeks Johnson wavered between a bombing halt and sending another 206,000 troops. Within the White House, Clifford led the cabal to convince their president that he ought to stop the bombing and thereby start negotiations that might end the war. "Is he with us?" a phrase from the French Revolution, became the code for those working toward a bombing halt.
Johnson's instincts told him that the North Vietnamese could not be trusted, and his fears made him worry that a bombing halt would be exploited by domestic political opponents. Still, in the end Johnson listened to those who urged that he stop the bombing. Addressing the nation on 31 March 1968, the president spoke of his willingness "to move immediately toward peace through negotiations." Johnson announced that "there is no need to delay talks that could bring an end to this long and this bloody war." He was "taking the first step to deescalate the level of hostilities" by unilaterally reducing attacks on North Vietnam, except in the area just north of the demilitarized zone, known as the DMZ. "The area in which we are stopping our attacks includes almost 90 percent of North Vietnam's population and most of its territory," said Johnson. "Even this very limited bombing of the North could come to an early end if our restraint is matched by restraint in Hanoi."
Johnson called on North Vietnam's leader, Ho Chi Minh, to respond favorably and positively to these overtures and not to take advantage of this restraint. "We are prepared to move immediately toward peace through negotiations." The United States was "ready to send its representatives to any forum, at any time, to discuss the means of bringing this ugly war to an end." To prove his sincerity, Johnson named the distinguished American ambassador-at-large W. Averell Harriman as his "personal representative for such talks," asking Harriman to "search for peace."
Then, in a dramatic gesture toward national unity, the president announced that he would not seek reelection, declaring, "I do not believe that I should devote an hour or a day of my time to any personal partisan causes or to any duties other than the awesome partisan causes of this office—the presidency of your country. Accordingly, I shall not seek and I will not accept the nomination of my party for another term as your president."
Three days later, Radio Hanoi broadcast the news that the DRV had accepted Johnson's offer and would agree to establish contact with representatives of the United States. This was the first time that Hanoi had said publicly that it was willing to open talks with the United States. Hanoi was careful to stipulate that these initial contacts would focus first on bringing about the unconditional end to American bombing and other acts of aggression against Vietnam.
On 3 May 1968 President Johnson announced that both sides had agreed to hold preliminary talks in Paris, but he cautioned that "this is only the first step. There are many, many hazards and difficulties ahead." The talks were scheduled to begin on 10 May. President Johnson knew that the government of South Vietnam (GVN), headed by President Nguyen Van Thieu, opposed any bilateral discussions with the North Vietnamese on issues that would effect the South. Thieu believed that North Vietnam would use these initial contacts to demand direct negotiations between the GVN and the NLF in the hope of creating the conditions for a coalition government. Thieu also feared the election of Vice President Hubert Humphrey, a Democratic president hopeful, who was slowly distancing himself from Johnson's position.
President Thieu believed that a Humphrey victory would bring a coalition government and a U.S. withdrawal. "A Humphrey victory would mean a coalition government in six months. With Nixon at least there was a chance," recalled Thieu. This view was shared by Vice President Nguyen Cao Ky, who remembered that "we had little desire to sit down with the communists at all, and no intention of sitting down with, and thereby recognizing, the National Liberation Front." Thieu thus decided he would not go to Paris even if there were a bombing halt.
President Thieu had two contacts in Washington: Anna Chennault, the widow of Flying Tigers hero General Claire Chennault, and Bui Diem, the respected South Vietnamese ambassador. Chennault was a central figure in the China lobby, a vehement anticommunist, and chair of Republican Women for Nixon. During the 1968 campaign Nixon, the Republican candidate for president, asked her to be "the sole representative between the Vietnamese government and the Nixon campaign headquarters." With Nixon's encouragement, Chennault encouraged Thieu to defy Johnson. The latter knew all about it, but his information had been obtained from illegal wiretaps and surveillance, so he could not do much with it.