Over the last three years, since Brexit and the Trumpening and the general rise of disreputable forces in Western politics, there has been a steadily boiling elite panic about the power of the paranoid fringe, the mainstreaming of conspiracy theories, the pull of fake news and the danger of alternative realities.

And yet over that same period, a good many members of the opposition to Donald Trump — a mix of serious journalists, cable television hosts, pop culture personalities, erstwhile government officials, professional activists and politicians — have been invested in what appears to be exactly the kind of conspiracy-laced alternative reality that they believed themselves to be resisting.

With the apparent “no collusion” conclusion to the Robert Mueller investigation, there will now be a retreat from this alternative reality to more defensible terrain — the terrain where Trump is a sordid figure who admires despots and surrounded himself with hacks and two-bit crooks while his campaign was buoyed by a foreign power’s hack of his opponent.

All of this is still true, in the same way that once the W.M.D. and Qaeda connections turned out to be illusory, Saddam Hussein was still a wicked dictator whose reign deserved to end. But as with the Iraq war, what has been sold, and often fervently believed, about l’affaire Russe has been something far more sweeping — a story about active collaboration and tacit treason and the subjection of United States policymaking to Vladimir Putin’s purposes, a story where the trail of kompromat and collusion supposedly went back decades, a story that was supposed to end with indictments in Trump’s inner circle, if not the jailing of the man himself.