The move, announced late Tuesday via a letter sent from President Donald Trump to Comey, marked the most unpredictable moment of a presidency that through its first 100-plus days has been the least orthodox in memory. It also ramped up criticism of Trump's judgments -- Comey was tasked with leading the investigation into Russia's meddling into the 2016 campaign and what, if any, collusion had occurred between Trump campaign operatives and Russian intelligence officials -- and left official Washington reeling over a move considered unthinkable as recently as this week.