"Trump ... belittled ... George Papadopoulos, who pleaded guilty ... to lying to federal agents investigating Russia's interference in the 2016 election, tweeting that 'few people knew the young, low level volunteer named George, who has already proven to be a liar,'" the WashPost reports.

Why he matters: "[I]nterviews and documents show that Papadopoulos was in regular contact with the Trump campaign's most senior officials and held himself out as a Trump surrogate as he traveled the world to meet with foreign officials and reporters."

• "Emails included in court documents ... show that Papadopoulos repeatedly told Trump campaign officials about his contacts with people he believed were representing the Russian government."
• "Papadopoulos sat at the elbow of one of Trump's top campaign advisers, then-Sen. Jeff Sessions, during a dinner for campaign advisers weeks before the Republican National Convention."