WASHINGTON (Reuters) - A judge will decide on Tuesday whether former national security adviser Michael Flynn should be sent to prison for lying to the FBI in a case stemming from the investigation into possible collusion between President Donald Trump’s campaign team and Russia in the run-up to the 2016 election. FILE PHOTO: Former U.S. National Security Adviser Michael Flynn departs after a plea hearing at U.S. District Court, in Washington, U.S., December 1, 2017.