Yeah, I suppose it depends on whether or not China would be willing to step in. I’m not sure since it has been a while since I studied it.
Having Operation Linebacker occur in say, 1964 would have made a world of difference.
Of course, DC still hasn’t gotten the message about meddling in military affairs.
I don't know about China...but in ‘68 I did spend some time tracking and trying to get a picture of Russian resupply helicopters coming across the border from Cambodia....(never did catch one...but some interesting stories none the less)