So, basically, what if the geopolitical divorce between the USSR and Maoist China in the late 1960's had actually escalated to war, rather than being isolated to a few border skirmishes?
Which side would be most likely to win?
From the looks of it, the PRC had a large army on paper, but i hear it was plagued by lack of experience and proper equipment, not to mention the lack of nuclear weapons. In comparison, the USSR and the Warsaw Pact had all three.
From where would the Soviet Union and associated WarPac armies attack China? I could see a massive-scale pincer movement with one army converging into the Chinese Plain from Manchuria and another crossing Xinjiang and Gansu to attack the west. Meanwhile, what sort of defensive strategies could China adopt?
How will associated states in Asia react?
Xinjiang seems likely to be detached from China no matter the outcome. I'm unsure as to the inclinations of the Tibetan independence movement -- could we see the Soviets sponsor a Tibetan rebellion, but one primarily socialist and detached from the Dalai Lama?
I'm also very curious about the possible stance of North Korea and Vietnam.
I could see the Red Army rushing to Pyongyang after securing Manchuria to keep South Korea and their American patrons from getting any funny ideas. Vietnam, meanwhile, could be affected by her sponsor states fist-fighting each other to the north -- could this mean that South Vietnam survives in the Mekong Delta region? I doubt Saigon could hold on to the pre-war equal division of the country, considering that the Tet Offensive already happened a year before, too.
Would the RoC in Taiwan make a second try at Project National Glory?
What about India? Would they see this as an opportunity to solidify their claims on Aksai Chin and Arunachal Pradesh?
What would be the long-term geopolitical effects?
Soviet attention and funds would have to be strictly diverted to the war with China, which could hamper their ability to fund far-left insurgency movements in the "third world". On the other hand, eliminating Maoism as a competing, sometimes American-friendly ideology could serve Soviet objectives well. Any thoughts on how the dynamics of the Cold War would change?
What are the effects on China in specific?
Lin Biao could be propped up as a pro-Soviet satrap in China in case of Soviet victory, but how stable would his position really be?
Would China still enact economic reforms like OTL's? It seems like it'd depend on who's lucky to survive the imminent purges of Mao or the following purges of the Soviet occupation force, but would the Soviets try and prop up China's command economy?