Hello,

I can paraphrase what I've learned about China from Henry Kissinger's On China and partially drawing upon my Eastern studies in college.

One thing I think you should understand is that the Russia and China were not allies in the same way that the United States and Great Britain are allies. As an American, I can go to Great Britain and generally understand the culture, read all the street signs, and have somewhat of a shared history.

In contrast, the Sino-Soviet alliance you're referencing was a marriage of convenience, and China's relations with Russia sweetened and soured during the Cold War just as much as American-Chinese relations had high points and low points during the Cold War.

China's foreign policy was largely guided by Mao for a majority of the cold war. Mao drew upon the full spectrum of Chinese history to form his image of how China should deal with other nations. To have a basic understanding of Chinese foreign policy towards Russia and the United States we must understand some of China's history.

China has historically viewed itself as the "Middle Kingdom", which for our purposes, we can simplify this to mean that it thought it was the world's preeminent technological and cultural power. For much of its history, this was indeed the case. This also begs the question, why didn't China become an empire? Many people look at the voyages of Zheng He and the consequent burning of a massive Chinese fleet. Middle and high school textbooks might pretend to be puzzled as to why this happens, but China's "Middle Kingdom" worldview holds the answer.

As the Middle Kingdom, China thought so lowly of other nations it deemed all other nations as inferior and not worth it to spend time, money, and lives expanding Chinese culture through force, (for the most part, at least compared to European powers that would follow later on) So, rather than build a military empire, and during the time of Zheng He's voyages, it certainly could have, China chose to pursue a policy of isolation, however it would welcome the "barbarian" nations to visit and learn from China so long the other nation recognized China as superior.

Flash forward to the 1900's. Mao, drawing heavily upon historical Chinese political / religious / nationalism (Which all three are sometimes indistinguishable) was not going to take a back seat to Moscow, the United States, or anyone else. Think of China as a kid that got bullied in middle school, worked out really hard over summer, and came to high school ripped. China was not going to get pushed around.

So, at times during the Cold War, China would purposefully chill relations with Russia and increase ties with the United States, and vice-versa. There was no enduring friendship between Russia and China nor any real kinship between the two nations simply because they were both communist. From China's standpoint, it would have been friends or enemies with anyone that would have furthered its goal of reclaiming its preeminent spot on the world stage.

TLDR: There was never really a split, China was always out for itself only and the Russian-Chinese friendship would have been thrown out the window if it felt it was being taken advantage of.

One of my favorite stories from Kissinger in On China was his story about Mao insisting that political negotiations take place in a pool because he knew that Khruschev couldn't swim and had to wear water wings, which he felt gave him an advantage during the discussions.

The relationship between the USSR and the PRC is discussed in a fair amount of detail in Frank Dikötter's Mao's Great Famine.

Full disclosure: Dikötter's conclusions on the death toll of the Great Leap Forward are disputed. However, as far as I'm aware, none of the criticism of the book has been about his depiction of the Communist leadership.

Ideology and personality are really only minor contributors to the split. It really came about because of the differing foreign policy objectives between the two.

Relations between the two nations started off rather chilly due to past Soviet support for the KMT during the Chinese Civil War, and while the two were relatively cordial for a time, things went downhill quickly. The Soviets were high-handed in their treatment of the PRC, because they saw themselves as the natural leader of international communism, a point which China contested. Relations deteriorated further when the Soviet Union began to get close with India, refusing to support the PRC in its 1962 border war against it. This decision was partly motivated by the outstanding border dispute between the PRC and USSR, which led to occasional outbursts of violence until the end of the Cold War.

In his article "Realpolitik Nationalism," Lei Guang argues that the PRC's foreign policy was driven by the need to assert itself after a century of colonial exploitation, and would have been peaceful had the USSR and India been more willing to negotiate. Instead, Moscow's haughty and inconsistent attitude towards Beijing made the two geopolitical rivals instead of ideological allies.

So to answer your what-if, it's not unreasonable to think that the two could have retained close ties throughout the Cold War, had the USSR been more diplomatic.

When Kruschev came to power Sino-Soviet relations were quite good: in 1953 the Soviet union gave Port Arthur and the Chinese part of the Far Eastern Railway back to China, so that was the high point of Sino-Soviet relations. Troubles started with the 20th Party Congress - Mao was worried that criticism of Stalin would be used against him by his inner party opposition - actually after the 20th Party Congress Mao did his famous provocation - the 'Hundred Flowers campaign' http://en.wikipedia.org/wiki/Hundred_Flowers_Campaign . (also I guess that a bit later on there was strong demand for an ideological enemy when the 'great leap forward' turned into an epic failure)

later things began to sour - Mao proposed to send Chinese workers to the Soviet Union, but Russia started to fear assimilation.

Interesting that in the late fifties the subject of China became subject of open discussion in the Soviet Union, and liberals there would lash out against Stalinism in China; the main audience here were Soviets, so that the subject of China was used here as a tool in the inner party struggle.

Interesting that this had a real adverse effect on Sino-Soviet relations, for example Zhou Enlai at the 22st party congress of the CPSU criticized Khrushchev for airing ideological differences in front of the world - that's when the Sino-Soviet rift became permanent.

Attempts at improving relations were made when Kruschev was sacked - for example a Chinese delegation visited Moscow. Later both China and the Soviet Union were supporting North Vietnam during the war there. Maybe without the Cultural Revolution there might have been an improvement in relations during the mid-late sixties.

I guess both the Soviet Union and China were societies where Ideology had an important function; so both were in permanent need of an ideological enemy - all for internal purposes. The Soviets did not have any mass repression campaigns after Stalin, so a far away enemy would not have to be suppressed, quite convenient as an ideological scarecrow.

In the late sixties and seventies there was much fear of war - at least on the Soviet side of the border; these inflated fears were used by all sides of the political spectrum.

Interesting that during the seventies advocates of closer ties with the west would also play the Chinese card, for example Solzhenitsyn proposed to improve ties with the west, all against what he regarded as the Chinese menace. He argued that Russia did not face any real threat from the West, while the threat from the East would be a real one.

source used: А. В. Лукин, Медведь наблюдает за драконом Образ Китая в России в XVII–XX веках; p 222-253 ; http://www.mgimo.ru/files/7069/7069.pdf

I don't feel incredibly qualified to give a true answer here, but this sounds to me like a topic better suited for /r/Historicalwhatif. In particular, here is an old post on that might have some ideas for you. The general ideas seem to be that either a union was incredibly unlikely thanks to the unfriendliness between Stalin/Mao (mind you, Mao admired Stalin's accomplishments, but the two were not friends), China's isolationary policies, and differing ideologies in general, or that diplomatic relations are never resumed in the early 70s by Nixon, leading to the eventual collapse of the Soviet Union and causing China to become a more inwardly focused, agrarian dictatorship akin to North Korea.