All of this hinges on the idea of Rhodesia being able to sustain itself; in all aspects Rhodesia was losing as the second phase of the Bush War came clear. Politically and socially Rhodesia was now at the end of its lifespan by 1976 and they couldn't win against the African nationalists. While an invasion of South Africa might not happen, and even if it did it wouldn't be in 1976, Rhodesia was already losing South African support in 1975-76 (fuel/munitions were limited, South Africa began an exit campaign, and economic assistance dried up). Their extension of conscription and service length started recruiting Africans and mercenaries to its rolls, with dissent against the conscription from reserve to active duty increasing. As well the use of CBW's showed just how desperate they were becoming at the end.
A war in 1976 would require either side to have significantly more support, and as some pointed, physical support a la Vietnam with the Soviets or the Chinese. If either ZANU or ZAPU were more armed and had greater support, Rhodesia wasn't going to win at the end of this.
I am sure Rhodesia/SA would put them on display quickly to make this in to us versus Soviet communists affair.
It already was a West v. East affair, being the largest proxy war in Africa, all it'd do is increase the intensity now that the cats out of the bag.
While the reasons for it may be understandable, to the extent frontline forces penetrate even briefly in to Rhodesia/SA, plus any guerilla forces, there are going to be some very ugly incidents (the Mau-Mau in Kenya). This combined with the Soviet involvement may give Rhodesia/SA a bit more slack internationally.
In more case, you'd see Rhodesia most likely go all out with their CBW now that their borders were breached and the conflict was now against them, and that'd create a much much larger incident. Rhodesia/SA wouldn't get a pass with the anti-Apartheid crowds now that they've gone off the deep end with the invasion. More than likely, once the CBW evidence comes up, it's going to dry up what remains of Rhodesian support.
Most likely they would want trade deals and a promise to stop supporting black nationalist partisans.
This would be fairly attractive prospects for a frontline state that takes heavy HEAVY casualties trying to invade as they most likely would do.
This would be borderline ASB, honestly. African nationalism was at an all time high and the conflict by 1976 was decisively in favour of the nationalists, and those frontline states had very little interest in ending the conflict now that Rhodesia was almost fully on the defensive. By 1977, the guerillas had become much more sophisticated and received support from Eastern advisors, and even if the average guerilla was still undertrained they were now much more prepared and much more ready,
Rhodesia will get some breathing room that might make a internal settlement with moderate nationalists possible in the long term.
It'd radicalize the conflict even further, considering one of the stipends of Ian Smith's accords in '76 was continued supremacy of whites even after the transition to majority rule. Any 'moderate' nationalists would've rejected it and demand full majority rule or there was no accord. Anyone who tried that would quickly find themselves ousted.
By the end stage of the Bush War battles were increasingly starting the resemble conventional operations, and the Rhodesians were still winning, so I'm not sure "Storming the Heavens" 5 years ahead of schedule would have yielded desirable results.
Having 12,500~ insurgents within your borders (and outpacing counter-insurgencies by Rhodesia with est. 38,000 in reserve), rounding up your citizens into virtual concentration camps for their safety, using chemical and biowarfare, seeing a population drain as well as economic turmoil and more in just two short years was the end stage of the Bush War. I fail to see how this is Rhodesia 'winning' in any honest case, they win battles but the war was done for them.
None of them could. It'd be like Israel-Arab conflict. Arabs attack Israel, Israel pushes them back, and does so good job doing so it's labelled aggressor. After international pressure Israel retreats, gives back most captured territory, then is condemned for not giving back all of it and more.
Political implications aside, this is untrue as I've shown above.
My military history isn't good, but not sure any of the frontline states could challenge SA and Rhodesia in a conventional war.
South Africa is your specialty Marius, how strong was South Africa in 1977 by your thoughts? Not just in military, in general, was there any serious unrest outside of anti-apartheid and others? Rhodesia was a no-brainer, it was over for them by 1976, but I'm not sure about South Africa.