The extraordinary but unverified documents published on Tuesday on Donald Trump’s ties with Moscow began life as a piece of opposition research, which has become as much a part of US politics as yard signs and coloured balloons.
There is a small industry of research and investigative firms in Washington, typically staffed by a mix of former journalists and security officials, adept at finding information about politicians that the politicians would rather stay hidden. The firms often do not know who exactly is hiring them; the request could come from a law firm acting on behalf of a client from one of the parties.
In this case, the request for opposition research on Donald Trump came from one of his Republican opponents in the primary campaign. The research firm then hired one of its sub-contractors who it used regularly on all things Russian: a retired western European former counter-intelligence official, with a long history of dealing with the shadow world of Moscow’s spooks and siloviki (securocrats).