Joe Raedle/Getty Images Sen. Elizabeth Warren became the most prominent Democrat and first 2020 presidential candidate to call on the House to begin impeachment proceedings against President Donald Trump on Friday afternoon. Warren made her case the day after special counsel Robert Mueller's redacted Russia investigation report was made public by the US Justice Department. "The severity of this misconduct demands that elected officials in both parties set aside political considerations and do their constitutional duty," Warren wrote in a series of tweets.