The light at the end of the tunnel, William Childs Westmoreland's critics would later joke, was a train headed toward the general, and on the night of 29–30 January 1968, it thundered through the RVN. On that date the enemy began its Tet Offensive, a countrywide series of attacks that would in short time effectively signal America's defeat in Vietnam. Coming just months after U.S. officials were so publicly optimistic about the war, the offensive instead validated the previous warnings of so many military officials and precipitated the final stage in the civil-military crisis that had been developing over the years prior to 1968. Militarily, the United States, after three years of intense combat, could not contain the enemy in southern Vietnam. Politically, the American people were no longer willing to support a war without measurable success or without an end in sight. When, on 27 February 1968, Walter Cronkite, broadcasting from Vietnam, urged disengagement from the war “not as victors but as an honorable people who lived up to their pledge to defend democracy, and did the best they could,” it was evident that the United States would not soon or successfully conclude its involvement in Indochina. “If I've lost Cronkite,” the president lamented, “I've lost middle America.” Lyndon Johnson, it went without saying, had lost the war as well.