In the sharpest escalation of the war since Operation Rolling Thunder ended in November 1968, U.S. fighter-bombers begin striking at North Vietnamese airfields, missile sites, antiaircraft emplacements, and supply facilities.
These raids continued for five days. They were begun in response to intelligence that predicted a North Vietnamese build up of forces and equipment for a new offensive. At a press conference on December 27, U.S. Defense Secretary Melvin Laird said the increase in bombing was in retaliation for the communist failure to honor agreements made prior to the 1968 bombing halt. As evidence, Laird cited the shelling of Saigon the week before, DMZ violations–including an infiltration route being built through the buffer zone, and attacks on unarmed U.S. reconnaissance planes. Pentagon figures showed that U.S. planes–with as many as 250 aircraft participating in some missions–attacked communist targets over 100 times in 1971, a figure comparable to U.S. air activity in the previous 26 months.
The intensified bombing spurred new antiwar protests in American. In New York, 15 antiwar veterans barricaded themselves inside the Statue of Liberty and flew the U.S. flag upside down from its crown. They ended their occupation of the monument on December 28, obeying a federal court order. At the same time in Washington, over 80 antiwar veterans were arrested after clashing with police on the steps of the Lincoln Memorial.