Strategy of Attrition in Vietnam

In contrast to the air attacks on North Vietnam, the U.S.-South Vietnamese war effort in the south was fought on the ground. In general, U.S. military forces in the region pursued a policy of attrition, aiming to kill as many enemy troops as possible rather than trying to secure territory.
By November 1967, the number of American troops in Vietnam was approaching 500,000, and U.S. casualties had reached 15,058 killed and 109,527 wounded. As the war stretched on, some soldiers came to mistrust their government's reasons for keeping them there, as well as Washington's claims that the war was being won. The later years of the war saw increased physical and psychological deterioration among American soldiers, including drug use, mutinies (мятежи) and attacks by soldiers against officers.
Bombarded by horrific images of the war on their televisions, Americans on the home front turned against the war as well: In October 1967, some 35,000 demonstrators staged a mass antiwar protest outside the Pentagon.

Impact of the Tet Offensive on Vietnam War

On January 31, 1968, some 70,000 DRV forces launched the Tet offensive, a coordinated series of fierce attacks on more than 100 cities and towns in South Vietnam. Though taken by surprise, U.S. and South Vietnamese forces managed to strike back quickly, and the communists were unable to hold any of the targets for more than a day or two.

With his approval ratings dropping in an election year, Johnson called a halt to bombing in much of North Vietnam in March (though bombings continued in the south) and promised to dedicate the rest of his term to seeking peace rather than re-election.
Peace talks between the U.S. and North Vietnam opened in Paris in May 1968. However, the dialogue soon reached an impasse (тупик). The Republican Richard M. Nixon was elected President.