On this date 40 years ago, President Johnson announced that he would stop all bombing of North Vietnam. This decision was tied to new peace talks with Hanoi. Operation Rolling Thunder, the name given to the Americans' bombing campaign, had lasted for 3 1/2 years. Wikipedia tells us that "Estimates of civilian deaths caused by American bombing in operation Rolling Thunder range from 52,000 to 182,000." Whatever the objectives of the campaign (and they were varied, changing, and often unclear), it is considered to have been a failure.
Near the end of Johnson's speech, which came just before the 1968 election, he stated:
I do not know who will be inaugurated as the 37th President of the United States next January. But I do know that I shall do all that I can in the next few months to try to lighten his burdens as the contributions of the Presidents who preceded me have greatly lightened mine. I shall do everything in my power to move us toward the peace that the new President--as well as this President and, I believe, every other American--so deeply and urgently desires.