The Lead With Jake Tapper

Some GOP Senators open to impeachment process; Sen. Paul: GOP may have to call Hunter Biden in trial; Trump supposed to be in Davos during start of impeachment trial; McConnell slams Pelosi for delaying impeachment trial; McConnell: Impeachment trial to start on Tuesday; Sen. Paul: If witnesses are allowed, I'll call for Hunter Biden; McCarthy: By holding articles, Pelosi helps Biden's 2020 bid; Sanders attacks Biden's Iraq war vote ahead of CNN Debate; Biden touts electability against Trump in new Ad; DNC Chair defends process over concerns about diversity; Warren aide: Not looking for a fight with Sanders tonight; New Biden Ad: Trump has Joe Biden on the mind; Barr & Pompeo shift justification for Iran strike; Trump on imminent threat: "It doesn't really matter"; Russia accused of hacking company at center of impeachment; Burisma hack seems to mimic Russia's 2016 election interference; Cyber firm: Russia began hack at height of Trump's impeachment; Schiff: Russia