Russiagate is an orchestration. It is the response of the military/security complex to Donald Trump's presidential campaign statement that he intended to normalize relations with Russia.
Trump recognized that the extreme Russiaphobia, which the hegemonic neoconservatives had whipped up since Vladimir Putin's statement at the Munich Security Conference in 2007 that Russia was a sovereign country and intended to act like one, was a threat to life on earth. The neoconservatives, who have controlled US foreign policy since the Clinton regime, are unwilling to accept limitations by any other country on Washington's ability to act unilaterally.
When Putin blocked the Obama regime's invasion of Syria and bombing of Iran, the neoconservatives paid Putin back by using NGOs and Ukranian politicians financed by Washington to overthrow the democratically elected government of Ukraine and to put in office a government hostile to Russia. The intent was to use Ukraine, a Russian province for more than three centuries, to create problems for Russia that would absorb Russia's attention and return a free hand to Washington and Israel in the Middle East and also to evict Russia from its Black Sea naval base in Crimea. When Crimeans voted to reunite with Russia, Washington misrepresented the democratic result of self-determination as a "Russian invasion and annexation of Crimea." Such an extraordinary misrepresentation destroyed any remaining confidence the Russian government might have had in Washington's veracity.
From here relations between the two nuclear powers deteriorated rapidly. As I and Stephen Cohen have emphasized, the danger of nuclear war is today far higher than ever during the long Cold War as there is today no trust whatsoever between the two governments.
Donald Trump is totally correct that nuclear war would be a terminable event and that nothing is more important than restoring a cooperative and mutually respectful relationship between the US and Russia.
The problem is that the military/security complex sees it differently. After 70 years of entrenchment the military/security complex is an independent political force. President Eisenhower warned the American people about this likely outcome in 1961 to no avail. From the standpoint of the military/security complex, the problem of normalizing relations with Russia is that it downgrades the "Russian threat" that is so essential to the $1,000 billion annual budget of the military/security complex and the power that such a massive budget conveys. Only 16 countries in the world out of 195 countries have a GDP greater than $1,000 billion. The military/security complex is large enough to be a member of the G-20 and to have its own currency and military.
Obama's CIA director, John Brennan, quickly organized the Russiagate conspiracy against Trump. Comey, Rosenstein, Clapper, Mueller, McCabe, Peter Strzok and others were, and are, apparently implicated as active participants in orchestrating an alleged collusion between Donald Trump and Vladimir Putin to steal the US presidential election. Based on deception of the FISA Court, warrants were illegally obtained that became the basis for appointing Mueller as a special prosecutor to construct by whatever means possible a case against President Trump.
After two years the only evidence we have of Russiagate is that it is a conspiracy against President Trump and the American people. Indeed, Mueller, fully aware that there was no Trump-Putin conspiracy, has not bothered to look for any evidence as there can be no evidence of something that did not happen. He pulled out of a hat some phony and meaningless indictments of some Russians in order to make it look like there was a conspiracy without having to prove it, but his main focus has been on framing Paul Manafort.