Week of December 17
In December 1965 the U.S. Marine Corps fought its second large-scale engagement against a main force Việt Cộng unit: Operation HARVEST MOON. By mid-November, the 1st Việt Cộng Regiment had recovered from the losses it sustained in Operation STARLITE, its first engagement with U.S. Marines in August 1965. The Communist regiment took advantage of the onset of monsoon season, and it moved during periods of poor weather, attacked isolated South Vietnamese Army outposts, and then set up ambushes to trap any relief efforts. Heavy rainclouds obscured visibility and limited the abilities of American air units to reconnoiter or conduct operations in the Phuoc Ha Valley in I Corps.
By early December, American and Vietnamese commanders in I Corps agreed to take action before the Việt Cộng established a strong base in the area. Operation HARVET MOON began on December 8, and combined U.S. Marine battalions in Task Force Delta with South Vietnamese Army units to uproot the 1st Việt Cộng Regiment. In the first days of the fight, the South Vietnamese troops sustained heavy casualties under Communist ambushes. Heavy fighting continued between the U.S. Marines and the 1st Việt Cộng Regiment until December 11, when the Communist forces withdrew.
The South Vietnamese I Corps Commander, General Nguyễn Chánh Thi, warned the U.S. forces to exercise caution before pursuing the retreating forces into a Việt Cộng base area. And at the suggestion of MACV, B-52 Stratofortresses bombarded the area before the Marines followed. Those Marine battalions that entered the Phuoc Ha Valley found little resistance, but a great deal of equipment. It was not until December 18 that pursuing Marines of the 2nd Battalion, 7th Marine Regiment encountered substantial Communist resistance, and heavy fighting ensued until the Việt Cộng forces withdrew again. Operation HARVEST MOON left 45 U.S. Marines killed and 218 wounded, and 90 South Vietnamese troops dead, 91 missing, and 141 wounded. On the Communist side, the engagement left an estimated 407 dead and 33 captured. 1
1Jack Shulimson and Charles M. Johnson, U.S. Marines in Vietnam: The Landing and the Buildup, 1965 (Washington, D.C.: U.S. Marine Corps History and Museums Division, 1978), 98–110; Spencer C. Tucker, ed., The Encyclopedia of the Vietnam War: A Political, Social, and Military History, 2nd Edition (Santa Barbara, CA: ABC-CLIO, 2011), 461-462; Shelby L. Stanton, The Rise and Fall of an American Army: U.S. Ground Forces in Vietnam, 1965–1973 (Novato, CA: Presidio Press, 2003), 40–43.