So now we know. The memo that has roiled Washington for the past few weeks is public, and with it comes an outline of the political case that Republicans will use to bolster Donald Trump’s position as the Russia investigation closes in on his White House.

It is both damning and trivial at the same time, yet another Rorschach test in a political maelstrom where actors see what they want to see.

At its heart is a demolition of the controversial golden shower dossier compiled by Christopher Steele, the former MI6 agent, alleging links between the Trump campaign and the Kremlin. And with it comes the charge that America’s intelligence services are biased against Mr Trump and his team.

In short, the four-page memo, drafted by Republican staffers for the House Intelligence Committee, alleges that intelligence services relied on the Steele dossier to sign off on surveillance of Carter Page, a Trump...