You are correct about he the unsuitability of terrain for conventional forces in Vietnam. I went back to visit Vietnam with my wife in 2000 and an M-48 tank that got mired up to its fenders while I was there in '66 is still there, exactly where we left it. That mud is like glue.
You still sound like the Air Force. i.e., "we still could have won that thing if we bombed more". I don't agree. Bombing does have an effect but it is not decisive. Resilient people just dig in and work around. When the trucks were interdicted, they used pack animals (including elephants), bicycles, and increased sea transport. After the war, we discovered that they were transporting a large percentage of war materiel via coastal shipping despite our navy blocade. By the way, the idea of breaching the Red River dikes was bruited about by Jane Fonda in 1971 as an example of our war criminality. She was lying, as always: we were attacking the POL loading facilities on the dikes -using conventional bombs - a heavily defended and legitimate target, not trying to "flood the Red River basin to cause the genocide of the Vietnamese people" as she said then.
You underestimate the commitment and involvement of the Soviets and the Chinese during the war. They invested Billions to ensure that the "National Liberation War" in Vietnam was successful. The Soviets infused the area with state-of-the-art antiaircraft systems and advisors and the Chinese also had advisors in North Vietnam and even in the South. One of our snipers killed a Chinese advisor as he was standing in a sampan near us. The ring he was wearing was big enough to slip easily over my thumb! (I didn't get the ring).
The Soviets and the Chinese were heavily invested in a communist victory and we would have seen the Chinese ground forces if we had landed in Vinh as planned. The Chinese PLA is primarily foot-mobile and they have lots of soldiers to expend. As I am sure you remember, they were very competitive with the Soviets for the leadership of the Communist world at that time, so I believe that the threat of Chinese intervention was very real.
The pro-enemy/"antiwar" organizations were led by old-line communist cadres supported by the Soviets and later directly by the NVA. At the top of the People's Coalitionfor Peace and Justice and the New Mobe you will find Irving Sarnoff and Dorothy Healey and Bettina Aptheker and many, many more hidden faces who corresponded with the enemy throughout the war. They received money and direction and followed their lead. The press (like today) camouflaged the whole movement as a "spontaneous reaction to an unjust war" but it wasn't to the movement's leadership. They knew exactly what they were doing and the NVA called the tunes from the timing and placement of demonstrations to the "thrust" (theme) of each event. The FBI knew all of this but no Attorney General inconvenienced anyone. Interesting, isn't it?
Agree that you and I could discuss Vietnam for a long time. And I agree that the government under our Commander-in-Thief, Lyndon ‘Silver Star recipient’ Johnson, wouldn’t act against the pro-enemy leftists because they were basically the Democrat constituency.
But irrespective what you and I believe (I viewed the war from the Lt/Capt perspective), here is what the admiral who would have done the targeting in NVN, had it not been for old Silver Star Lyndon, believed. Adm Sharp is on the record that the US military could have successfully won the Vietnam War any time that President Johnson chose after 1966:
“Once the decision was made to participate in this war and engage Americans in the military conflict, I believe we should have taken the steps necessary to end the war successfully in the shortest possible time. It was folly to commit Americans to combat and then force them to fight without utilizing the means we so richly possessed to win an early victory. It is my firm belief, however, that we did exactly that by not using our air and naval power to its full effectiveness. . . . . We could have brought the Vietnam War to a successful conclusion in short order, early in the game, once the decision had been made by the civilian leadership to engage with US forces. All we needed to do was assemble the necessary force and then use it the way it was designed to be used. (I do not include atomic weapons in my definition of necessary force. In my view, there was never a need for employing nuclear devices in Southeast Asia, and I never recommended such.) In fact, we assembled the necessary force quite rapidly. By mid-1965 we had strong air power available. By 1966 we had the full measure of air power to do the job, and our ground forces were strong enough that in combination with such air power properly applied we could have forced Hanoi to give up its efforts to take over South Vietnam. But authority to use our air power to this end was simply not forthcoming.”
Admiral U.S. Grant Sharp, Strategy for Defeat: Vietnam in Retrospect, Presidio Press, 1978, pp. 2-3.