After years of extensive fighting in Vietnam, Laos and Cambodia the US had been facing problems both at home and at abroad hatred toward the war was high and support low in the US, fearing that the South Vietnamese Government would back down do to the constant pressure by the North, Nixon decided to launch one final attack in 1972 to inflict the North as much damage as possible. Operation Calling Back would compose of a direct American Invasion of the North in both Land, Air and Water as an Amphibious Invasion would be launched, on November 18th American Forces were once again amassed on the Gulf of Tonkin many believed that they would once again be forced to enter Vietnam but this time through the North.
On the night of the 20th a massive bombing campaign that lasted some four hours cleared the landing zones for paratroopers and the beaches were cleared so that infantry and tanks could be brought over, the day before on the 19th the Americans had launched an offensive across South Vietnam prompting the Viet Cong to send reinforcements along with the North Vietnamese Army in case the Americans broke through leaving the road to Hanoi very undefended. The beaches were easily secured and by the time the sun rose there were around 3,500 Americans on the beaches along with 100 tanks and 125 vehicles paratroopers had already cleared the pathway to continue inland, were they were to face minor resistance. As Nixon presented the new Offensive massive protests and international condemnation on the continuing of the war this time in the North, the American Air force which was at the moment at the highest concentration during the war hit important border points in North Vietnam in the effort of preventing Chinese forces entering North Vietnam. With a straight pass to Hanoi passing along the Red River, the tanks began to rush in heading for the city supported by infantry many called this the "New American Blitzkrieg", the North Vietnamese Army was quickly faced with various problems as the Americans began to bomb the back of the North Vietnamese forces and the Viet Cong forcing them into heavy casualties do to the bombings.
On the night of the 22nd the Beaches were heavily struck but with Air support the forces were pushed back, facing steep resistance around tt. Cổ Lễ were North Vietnamese forces armed with Chinese equipment stooped the American Tanks but after heavy bombing they were virtually destroyed and the attack continued. The Chinese government decided to prepare a massive convoy of 100 tanks and around 200 vehicles to help the North Vietnamese and as the force was around the border the American forces bombed the area, after heavy bombing what vehicles and tanks remained were forced to retreat back across the border, an attack the Chinese government outraged claimed that the material had been destroyed inside China not in Vietnam but after evidence revealed that they were destroyed around five km away from the border the Chinese were forcefully silenced.
On the 23rd the Soviets condemned the new offensive on the United Nations Forum, and asked for sanctions on the US. The thrust continued along the Red River facing only minor defensive positions, which were easily pushed back and destroyed. On the night Chinese Commanders along with Soviet Advisors and a force of 50 tanks and 79 vehicles along with some 3500 men entered the North through various points and met in Hanoi early on the 24th, the delegation began talking about a Counter Push on the American spearhead around Nam Dinh which had just been recently captured. An attack on the right flank of the the American forces would cut off a large force which would had advanced deeply inside, the plan was to retreat the North Vietnamese positions back 25 Kilometers to allow for a more strong defense and with support of the Chinese attack they would hold up the American attack. The Chinese attack was planned to be launched on the 26th and the North Vietnamese were to retreat in the night of the 25th.
The Americans kept there push as more and more resources arrived at the beaches, and with the expansion of the perimeter more Armor could come in. The Chinese forces began to mass for the attack and began to prepare bridges to cross the river, American intelligence suggested the possibility of major Chinese forces in the area, as reports grew the American forces decided to launch a major bombing operation on the right river bed. The Chinese forces were able to just barely escape the night bombings on the night of the 24th, as fear of a flanking attack grew more and more each hour the American forces with new forces reinforced the flanks, but the defenses only came up to Nam Dinh meaning that the Chinese attack would hit an empty flank. As the Americans resumed their push in the morning they faced no resistance the Americans thought that the Vietnamese were defeated and didn't out much attention on the fact.
At 9am the Chinese forces stormed the river bed in just 15 minutes Chinese amphibious vehicles had established a beach head and easily placed a bridge, but to much coincidence a patrol who got lost identified the bridge and warned the rest of the army. To counter the attack a heavy bombardment was ordered but it was cancelled mid-air do to heavy Anti-Aircraft guns, so an armored attack was approved to much of the American luck the armored push was stopped just 3 km from the main North Vietnamese line, heavy artillery was able to hit the bridge and render it useless for the rest of the day. At night the second bridge was established just as the American tanks hit the perimeter, with coming reinforcements from the second bridge they were able to repulse the attack with heavy casualties. As the bridge head began to grow the American forces began to fear of a Chinese breakthrough, and so launched a bigger attack as the first bridge was re open. The new attack was able to inflict heavy casualties on the Chinese forces and almost closed the first bridge, the North Vietnamese forces held their positions with ease, in fear of an attack from the north decided to bomb the route, the North Vietnamese forces suffered 2500 casualties and were forced back.
The Chinese bridgehead attempted its first breakout attack which resulted in the loss of all tanks involved and vehicles after anti-aircraft guns weren't able to stop an incoming bombing run, a renewed American attack was able to crack open the first bridge and it was occupied and after a heavy bombardment along with an increase in the river resulted in the second bridge collapsing leaving 10 tanks, 25 vehicles, and some 800 man trapped on the other side of the river, this forces had been cleared out the next morning. With the Chinese threat cleared on the 30th the push continued facing only minor defensive positions along the way. With Hanoi in reach for a massive American push, the North Vietnamese delegation began to panic Chinese and Soviet reinforcements would take time to arrive and would not be able to defend Hanoi immediately, and with the Viet Cong suffering heavy damage in the south and with pressure from Chinese and Soviet advisors, the North Vietnamese forces signed a ceasefire agreement at midnight.