John McCain has never been a fan of Donald Trump.

He undermined him on the campaign trail, and has opposed the America First agenda.

But now he was caught in his biggest betrayal.

The Christopher Steele dossier kicked off the media allegations of Russian collusion.

Steele – an ex-British Intelligence agent – prepared an opposition research memo that was commissioned by Fusion GPS – a firm with ties to Hillary Clinton.

The memo contained outrageous – and later debunked – assertions about Russian prostitutes, collusion and blackmail.

This so-called “dossier” ended up in the press because then-FBI Director James Comey briefed then-President elect Trump on its existence in early January.

Critics believe Comey only briefed Trump on the memo so the fact that Trump was informed of it could be leaked to media and the press could report its contents.

But how did Steele’s memo get into Comey’s hands?

The answer is Senator John McCain.

When McCain learned of it, he dispatched a trusted aide to Britain to retrieve a hard copy that was then passed to Comey.

The Guardian reports:

In mid-November, the documents took another route into Washington that ultimately led to them being mentioned in the joint intelligence report on Russian interference that was delivered to President Obama and President-elect Trump. On 18 November, the annual Halifax International Security Forum opened in the Canadian city, bringing together serving and former security and foreign policy officials from around the world.

Senator John McCain, a hawkish Republican, was there and was introduced to a former senior western diplomat who had seen the documents, knew their source and thought him highly reliable. McCain decided the implications were sufficiently alarming to dispatch a trusted emissary, a former U.S. official, to meet the source and find out more.

The emissary hastily arranged a transatlantic flight and met the source at the airport as arranged. (The Guardian has agreed not to specify the city or country where the meeting took place.) The meeting had a certain cold war tradecraft to it, as he was told to look for a man with a copy of the Financial Times. Having found each other, the retired counter-intelligence officer drove the emissary to his house, where they discussed the documents and their background.

The emissary flew back within 24 hours and showed McCain the documents, saying it was hard to impossible to verify them without a proper investigation. McCain said he was reluctant to get involved, lest it be perceived as payback for insulting remarks Trump had made about him during his rambunctious campaign.

However, on 9 December, McCain arranged a one-on-one meeting with Comey, with no aides present, and handed them over.

“Upon examination of the contents, and unable to make a judgment about their accuracy, I delivered the information to the Director of the FBI. That has been the extent of my contact with the FBI or any other government agency regarding this issue,” the Senator said in a statement on Wednesday morning.

Conservatives were livid at McCain’s betrayal.

He injected the collusion hoax into the media bloodstream by passing the fake news memo to Comey.

Do you think this was John McCain’s worst betrayal ever?

Let us know in the comment section.