So Don is against the war. I guess this is because of his experience in Korea. But back in the 60's, even vets were mostly for the war so this seems a bit unusual for Don. It also places him in bed (so to speak) with a gaggle of folk he would not like to be seen with publicly. The characeter has evolved at least in some areas, so perhaps this is a continuation of his journey.
By January-February 1968 and the Tet Offensive majorities had firmed up the view that the decision to enter the war had been "a mistake."**it's a big part of the reason that LBJ didn't run for reelection that year.