This is coolbert: The Marine force at Khe Sanh (KS) in my opinion would have been able to successfully defend against an all out ground assault by the North Vietnamese Army (NVA) at KS. The NVA would not be able to do to the Marines what they were able to do to the French at Dien Bien Phu (DBP). 20,000 attacking NVA would not be able to overcome 5,000 Marines as 40,000 Viet Minh were able to defeat 10,000 French troops. Number of reasons for this. These would include:

The Marine force was a homogeneous force, not mixed as was the French garrison at DBP. Had a unified command that was determined and was not going to be surprised. Marines were just better prepared.

The Marines had superior organic firepower, training, experience, and esprit than the French did at DBP. This is not to negate the actions of the French force, just that the Marines would have been better.

The Marines were able to call upon not only their organic firepower, but an enormous and overpowering amount of fire support from other services. This would have included of course, Arc Light [USAF], Navy and Marine tac air, and Army [helicopter gunships].

And, in addition, of course, is the fact that the U.S. high command in Vietnam, led by Westmoreland, was just not prepared to see the garrison at KS be a victim and fall to a NVA assault. They were prepared to do whatever was necessary to emerge victorious.

This is not to say that the attacker at KS, the NVA, could not have assaulted the garrison at KS and caused a lot of damage. They could have. But they would not have emerged victorious.

coolbert.