Talk to a supporter of US President Donald Trump and, at some point in the conversation, you are likely to hear some version of this riff: "The mainstream media is fake news. They ignore all the good things Mr Trump is doing because they hate him and wanted Hillary to win. That's why they spend so much time on this ridiculous Russia story and not enough time investigating whether Trump Tower was actually wire-tapped!"
Talk to an opponent of Mr Trump (pictured inset) and, at some point in the conversation, you are likely to hear some version of this riff: "Russia has something on Mr Trump. Michael Flynn, Jeff Sessions, Paul Manafort and the president's own unwillingness to badmouth Vladimir Putin and Russia all make clear that he is being secretly controlled by a foreign power. He needs to be impeached!"
We live in 'X-Files' time now; conspiracy theories aren't dismissed, instead they are taken as something close to fact. "Prove that the conspiracy theory is wrong!" is now our default position.
Conspiracy theories have always been with us - there was a second shooter in the JFK assassination, 9/11 was an inside job - but have almost always existed on the fringes of political dialogue. Not anymore. We are all conspiracy theorists.
Here's what Paul Musgrave, an assistant professor at the University of Massachusetts Amherst, wrote recently about the subject: "Less than two months into the administration, the danger is no longer that Mr Trump will make conspiracy thinking mainstream.
"That has already come to pass. Conspiracy theories, rumour and outright lies now drive the news cycle, as the weekend demonstrated once again. (Earlier examples included Mr Trump's false claim about widespread voter fraud and his misrepresentations about a Navy Seal raid in Yemen.) Far worse, such untruths may now be driving government policy in realms as disparate as immigration policy and civil rights. In the long term, the damage done to trust by the normalisation of untruth may threaten the social contract on which democracy itself rests."
It's important to remember how closely Mr Trump's roots in politics are tied to his willingness to embrace conspiracy theories. His candidacy was made possible by his embrace of the disproven idea that former president Barack Obama wasn't born in the United States. During the course of the 2016 campaign, he regularly brought conspiracy theories to the centre of the conversation.
He sat down with noted conspiracy theorist Alex Jones and promised he would do the same as president (he hasn't - yet). He suggested that rival Republican presidential hopeful Ted Cruz's father was part of the plot to assassinate John F Kennedy.
That conspiracy flirtation has continued as president - with the wire-tapping tweets as the most prominent example.
Mr Trump seems entirely comfortable taking a conspiracy theory and, with scant evidence it is anything more than that, push it into the mainstream. Mr Trump's assertion that he had evidence to prove the claims made by conservative talk show host Mark Levin and championed by Breitbart News turned out to not be true - or at least not true yet.
And, the Trump White House is now trying to claim victory and move on, insisting that Mr Trump's only goal was to get congressional committees to look into the allegations in search of evidence - evidence he insisted he already had.
What Mr Trump knows is that for many of the people who support him, the fact that he has not offered any actual evidence of the wire-tapping is besides the point. Of course the evidence isn't readily available - the political establishment is doing everything it can to cover it up and make Mr Trump look bad! So severe is the distrust directed at the media that if the media says there is not factual basis for Mr Trump's claims, that functions for his supporters as a sort of testimonial that he must be right.
On the other side of the political spectrum, there is the growing sense among Democrats that Mr Trump is, in some serious way, in hock to the Russian government. That Mr Trump's former national security adviser Michael Flynn and current Attorney General Jeff Sessions both misremembered conversations they had with Russian Ambassador Sergey Kislyak is taken as certain evidence of this fact.
As is the fact that Mr Trump refuses to issue a stern condemnation of Mr Putin and Russia. Or call for an independent investigation into the ties between Mr Trump's campaign and Russia.
As always, conspiracy theories could be true. The most prominent example is the reporting the 'National Enquirer' did in the 2008 presidential campaign about a child then Democratic Senator John Edwards had fathered out of wedlock.
But, for every one conspiracy theory that winds up being right, there are a thousand - or a million - that are totally without merit. That used to be a sentence that 98pc of the population could agree on. No longer. Our retreat into partisan camps, the rising dislike and distrust of "elites", the surge in partisan media outlets and the collapse of trust in the mainstream media has created a toxic environment in which conspiracy theories not only can bloom but are nurtured.
We all now see the hidden hand of government/media/corporations/foreign entities behind everything everyone does.
And, what's worse, there's no trusted source of facts that we all agree can be used to debunk conspiracies.
Conspiracies grow and grow.
And we believe them in ways we've never done before.