In this conference call with three 1968 presidential candidates, President Johnson reviewed recent developments on Vietnam and his conditions for imposing a total bombing halt on the North. Hanoi had demanded a cessation of bombing in order for peace talks to move forward; for his part, Johnson needed assurance that the North Vietnamese would refrain from shelling civilians in South Vietnamese cities, respect the Demilitarized Zone [DMZ] between North and South Vietnam, and consent to Saigon's participation in peace talks. Hanoi's move toward acceptance of those conditions had set the stage for a bombing halt—and the emergence of a new dynamic in the U.S. presidential race.