The impeachment hearing into US President Donald Trump has focused overwhelmingly on his attempts to trigger an investigation into a political opponent, former vice-president Joe Biden.

But on the fifth day of the hearing, a witness pointedly addressed the second, often overlooked favour Trump was asking for.

"Some of you on this committee appear to believe that Russia and its security services did not conduct a campaign against our country, and that perhaps, somehow, for some reason, Ukraine did," said Dr Fiona Hill, formerly senior director for European and Russia affairs on Donald Trump's National Security Council.

"This is a fictional narrative that has been perpetrated and propagated by the Russian security services themselves."

Yet it's not just the Russian security services and Trump-friendly Republican congressmen who have been propagating this fictional narrative.

The President has done so himself.

Senate Minority Leader Senator Chuck Schumer with a copy of the transcript of a phone call between President Donald Trump and the President of Ukraine. ( AP: Jacquelyn Martin )

In the transcript of the call he made on July 25 which triggered the impeachment inquiry, President Trump asked his Ukrainian counterpart to look into it.

"I would like you to find out what happened with this whole situation with Ukraine, they say Crowdstrike ... I guess you have one of your wealthy people ... The server, they say Ukraine has it. There are a lot of things that went on, the whole situation," said President Trump.

"They say a lot of it started with Ukraine—."

When the President says "they", he's referring to his convicted felon campaign director Paul Manafort and his personal lawyer Rudy Giuliani.

And "the whole situation" he's referring to is a conspiracy theory surrounding the Democratic Party's email server.

The cybersecurity conspiracy theory

When it was discovered that this server had been hacked ahead of the 2016 election, a cybersecurity company called CrowdStrike was called to investigate.

This was one of their areas of expertise — they had previously investigated a Chinese military hack of US corporations, and the North Korean hack of Sony Pictures.

CrowdStrike quickly determined that the perpetrator of the hack on the DNC servers was Russian military intelligence.

And this is the point where the conspiracy theory begins.

The allegation is that CrowdStrike is owned by a Ukranian oligarch, and that he told his technicians to plant digital evidence that Russia was responsible for the hack — essentially framing Russia for the crime of election interference.

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Additionally, the theory goes that CrowdStrike spirited the server away to be hidden in Ukraine, where nobody could determine the truth.

The theory has been repeatedly debunked.

For one thing, CrowdStrike is a California-based, publicly traded company, not the personal fiefdom of its Chief Technology Officer Dmitri Alperovitch, who was born in Russia, and has lived in America since he was 14.

Secondly, the "server" is actually 140 servers, mostly in the cloud, and were never physically on Democratic Party property.

Saying "the server, they say Ukraine has it" is nonsensical.

Standard procedure for investigating cybercrime is to create an exact copy of your files and hand that over to authorities, which is what the DNC did.

The theory is, according to any expert in the field, is nonsense.

US President Donald Trump has been propagating a fictional narrative about Ukraine. ( Reuters: Tom Brenner )

So where did Trump get the idea from?

According to testimony by senior Trump campaign official Rick Gates — it came from a man with close ties to Russian Military Intelligence.

Konstantin Kilimnik, a business associate of Gates and Trump campaign director Paul Manafort from their time working in Ukraine, suggested to Manafort that Ukraine may be responsible as soon as news broke about the hack.

This theory was amplified by the Russian President Vladimir Putin himself, who in a February 2017 press conference alleged that Ukraine had supported Hillary Clinton's campaign.

"We all know, during the presidential campaign in the United States, the Ukrainian government adopted a unilateral position in favour of one candidate," Putin said.

By the time Putin and Trump had their first official summit in mid-2018 in Helsinki, Finland, the idea had firmed in Donald Trump's head.

Following a two hour closed-door meeting with President Putin, Trump raised the issue of the server.

"Where is the server? I want to know, where is the server and what is the server saying?" Trump said.

US President Donald Trump and Russian President Vladimir Putin in 2017. ( Reuters: Sputnik/Mikhail Klimentyev/Kremlin )

Moments later, he said he took President Putin at his word on the issue of 2016 election interference.

"He just said it's not Russia. I will say this. I don't see any reason why it would be, but I really do want to see the server," he said.

As opposed to an investigation into Joe Biden, it's difficult to see how an investigation into Ukrainian election interference in 2016 helps President Trump politically.

It's far easier to see how it benefits President Putin though.

Putin has no hope of seeing US sanctions on his country lifted while he is being blamed for the 2016 DNC and Clinton campaign hacks.

And if he wants to pull a similar trick in 2020, he would prefer the US was trying to defend themselves against Ukrainian oligarchs than Russian military hackers.