I don't see how you can equate US forces in Vietnam with Ukraine considering peace talks to end the war in their country.
If the US invaded Mexico, he would presumably consider the US invasion a war crime but might still consider Mexico making concessions their best course of action. It wouldn't be that he supported the US's war, continuing to fight is not always the best option for the people.
>continuing to fight is not always the best option for the people
People who let themselves/are forced by rest of the world (Yalta) be conquered by soviets end up murdered by the xxx thousands https://en.wikipedia.org/wiki/Katyn_massacre, raped en masse, send to Siberia, and their land plundered down to bricks and pipes. We have seen that 100 years ago, 80 years ago, and we see this today with russian soldiers stealing toilets from conquered Ukraine.
> I don't see how you can equate US forces in Vietnam with Ukraine considering peace talks to end the war in their country.
Why? What makes peace negotiations in Vietnam (1968-1973) different from peace negotiations in Ukraine, and how is it relevant?
> If the US invaded Mexico, he would presumably consider the US invasion a war crime but might still consider Mexico making concessions their best course of action.
Well, he didn't call for negotiations or any concessions or from the Vietnam side, instead explicitly called for unilateral pull-out of US forces.
If the US invaded Mexico, he would presumably consider the US invasion a war crime but might still consider Mexico making concessions their best course of action. It wouldn't be that he supported the US's war, continuing to fight is not always the best option for the people.