When thinks about possible conspiracies between Putin and Trump, we should not forget that according to H.R. Haldeman, in the summer of 1969, the Soviet Union asked Nixon to join them in a nuclear attack on China, and that when Nixon said that he would not, the USSR asked if America would standby as a neutral party while the USSR attacked China. Per the following linked articles, this request precipitated Nixon's madman policy and eventually to Nixon playing the 'China Card'.
However, it is conceivable that if Trump is in league with Putin, that they could use the unfolding of the North Korean nuclear crisis as an opportunity for a joint nuclear strike on China, before China becomes the dominate power in the world:
Title: "Soviet Denies Plan to Attack China, Calls Assertion by Haldeman .a Lie"
http://www.nytimes.com/1978/02/18/archives/soviet-denies-plan-to-attack-china-calls-assertion-by-haldeman-a.htmlExtract: "The official Soviet press agency Tass today described as “a lie from beginning to end” the assertion by H. R. Haldeman, the former White House chief of staff, that the Soviet Union asked the Nixon Administration in 1969 to join it in a nuclear attack against China.
“Haldeman's nonsensical statements are a lie from beginning to end and pursue provocative, and only provocative, aims,” Tass said in an unusually quick and categorical. response to the publication in the United States today of excerpts from Mr. Haldeman's book, “The Ends of Power.”"
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Title: "Nixon intervention saved China from Soviet nuclear attack"
http://www.scmp.com/article/714064/nixon-intervention-saved-china-soviet-nuclear-attackThe Soviets moved thousands of troops to its far east and prepared missiles armed with nuclear warheads. It told its allies in eastern Europe that it planned a nuclear attack 'to wipe out the Chinese threat and get rid of this modern adventurer'.
On August 20, the Soviet ambassador in Washington told Kissinger of their plans and asked the US to remain neutral. Wishing to stop the attack, the White House leaked the story to The Washington Post. Its edition of August 28 reported that the Soviet Union planned to launch missiles with hundreds of tonnes of nuclear material on Beijing, Changchun , Anshan and its missile-launch centres of Jinquan, Xichang and Lop Nor.
In late September and October, war fever in China reached its peak. Lin ordered the army to move from its bases and residents of major cities to dig shelters and store food.
In the final step before the attack, Moscow sought the opinion of Washington. Nixon saw the Soviet Union as his main threat and wanted a strong China against it; he feared the effect of a nuclear war on 250,000 US troops in the Asia-Pacific. On October 15, Kissinger told the Soviet ambassador in Washington that the US would not be neutral and would attack Soviet cities in retaliation.
Bluff or not, it worked. 'The Americans betrayed us,' the ambassador said. They called off the attack on October 20 and began negotiations with China in Beijing. The crisis was over.
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Title: "Forgotten Fact: Russia and China Almost Started a Nuclear War in 1969"
http://nationalinterest.org/blog/the-buzz/forgotten-fact-russia-china-almost-started-nuclear-war-1969-21398Extract: "… CIA director Richard Helms had informed the press that the Soviet leadership had been discreetly inquiring with foreign governments about their opinion on a preemptive strike on China.
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If the Soviet Union had chosen war, it would have had two choices. The first choice would have been a conventional mechanized attack into Manchuria, where much of China’s industry was located, coupled with a limited “counterforce” nuclear strike against Chinese nuclear forces and nuclear-research facilities. A Soviet attack into Manchuria in 1969 would have resembled the invasion of the same region in 1945 against Japanese forces, and would likely have followed the same invasion routes. Such an attack would likely have been more modest in scope and focused—the 1945 attack had been carried out by 1.5 million troops by a fully mobilized Soviet Union. An attack in 1969 would likely have been carried out by half as many troops but with more firepower, supported by modern armor, artillery, tactical air forces and possibly even tactical nuclear weapons.
A second option would have been the same nuclear strikes against China’s new nuclear-weapons program without an accompanying invasion of Manchuria. China had tested its first nuclear weapon in 1964 and conducted its first underground nuclear test in 1969. It is not clear whether or not any of China’s nuclear weapons would have been useable in a war with the Soviet Union, but Moscow could not have afforded to find out the hard way. One major question is whether or not the Soviet Union would have coupled an attack on China’s nuclear weapons with a thermonuclear attack on Beijing and China’s leadership. An attack on Beijing by just one Soviet SS-8 intercontinental ballistic missile, armed with a 2.3-megaton thermonuclear warhead, would have obliterated the city and killed more than half of the city’s 7.6 million residents."
See also:
Title: "The Nukes of October: Richard Nixon's Secret Plan to Bring Peace to Vietnam"
https://www.wired.com/2008/02/ff-nuclearwar/