Comparisons with Vietnam are really not accurate. That was a war against a tough enemy who were causing hundreds of dead/wounded per month. In September 1968, there were over 2100 dead.
The terrorists who occasionally are blowing things up in no way compare to the NVA. This is in large measure why we can get away with occupying the country with a volunteer force where the gals are serving in uniform while "George P" is at law school.