Former Trump confidant Roger Stone. Photo: Michele Eve Sandberg/REX/Shutterstock

There are many people in the Trump campaign who had lines of communication with Russia that may have been used for collusion during the 2016 campaign: Paul Manafort, Michael Cohen, Michael Flynn, and Donald Trump Jr. But probably nobody in this realm faces clearer peril than Roger Stone.

There is a large and growing pile of evidence suggesting Stone had contacts with WikiLeaks during the campaign, which enabled him to flaunt his advance knowledge of stolen Democratic emails. (The latest addition to the pile is that, on a conference call selling his political insight, Stone “told callers about WikiLeaks’ plans to release information that he said would affect the 2016 presidential campaign,” reports The Wall Street Journal.

Yesterday, the Washington Post reported on Stone’s jeopardy. What makes the Post story novel, and potentially more explosive, is that it reports not only that Robert Mueller is investigating Stone’s back channel to WikiLeaks, but also his “private interactions with senior campaign officials.”

Here’s why this is significant. Stone communicated regularly and directly with Trump during the campaign. The odds that Stone, a notorious braggart seeking to curry favor with Trump — notorious also for being unhindered by ethical scruples — would fail to share his knowledge of what the hackers had up their sleeves are extremely remote. The catch is that, unless he recorded it in a memo, it will be hard to prove that Stone told any of this to Trump. Stone has been publicly vowing, “I will never roll on Donald Trump.” (Just what you’d say when both of you are innocent!) And Stone, unlike other vulnerable Trump officials, does not appear vulnerable to any state-level charges, which means Trump could (and almost certainly would) pardon him if he keeps his promise not to turn over any evidence implicating the president.

But if, as the Post implies, Stone shared his inside knowledge about WikiLeaks with other Trump campaign officials, then it might not matter if he keeps his mouth shut. Those officials, some of whom have rolled on Trump already, could tell Mueller what Stone knew, and even what he told Trump. One likely candidate to have heard some word from Stone is Paul Manafort, Stone’s former business partner and a current Mueller witness. That testimony could very easily establish Trump’s role as an accessory after the fact to Russian hacking.

Stone has made a career out of being a dirty trickster who seeks the limelight. If he boasted about the wrong thing to (or in front of) the wrong person, that habit could come back to bite him, and Trump.