As recently as February, special counsel Robert Mueller's team dropped hints that the inquiry into Russia's role in the 2016 U.S. election might unearth evidence of active cooperation between Moscow and President Donald Trump's campaign.

That turned out not to be the case. Attorney General William Barr, who has said he hopes to release Mueller's nearly 400 page report this week, told U.S. lawmakers on March 24 that the special counsel investigation "did not establish that members of the Trump campaign conspired or coordinated with the Russian government in its election interference activities."

To be sure, the investigation documented numerous contacts between Trump campaign figures and Russia, a willingness on the part of the campaign to accept help from Moscow, and no indication that the campaign told the Kremlin to keep out of an American presidential race.