CNN The Lead w/ Jake Tapper

Sources: House Republicans no longer expected to defend Trump in impeachment trial; Sources: Trial expected to start with contentious day with Democrats trying to force witnesses; Pompeo says State Department will investigate possible surveillance of ex-U.S. Ambassador; Indicted Giuliani associate says he watched Trump order aide to fire U.S. Ambassador to Ukraine in 2018; Eleven troops being treated for concussion symptoms, transported from Iraq to Germany and Kuwait; Defense Official to CNN: Symptoms emerged days after the attack; Iran's Supreme Leader says U.S. was slapped in the face; Trump: Impeachment trial is "rigging the election again against Bernie Sanders"; Trump knocks Bloomberg campaign Ads as "vanity project"; Biden to NYT Editorial Board: "Not true" I hinted willingness to serve only one term; FBI arrests three alleged white supremacists ahead of gun rights rally in Virginia; New book: Trump "dressed down" top military officials in 2017 meeting, called them losers; 

House managers formally present articles to Senate; Senate expected to vote on whether to call trial witnesses; John Dean: I'd be astounded if Senate doesn't call witnesses; Senate impeachment starts as Giuliani associate implicates Trump; Ukraine's FM: I don't trust a word Parnas is saying; Ukraine launches investigation after text messages suggest surveillance on former U.S. Ambassador; Lawyer releases video showing Trump with Parnas at Mar-a-Lago; GAO: Trump Admin broke law by withholding Ukraine aid; Trump (again) insists he doesn't know Parnas after explosive claims implicate him in Ukraine scandal; Trump claims no knowledge of Rudy Giuliani letter to Zelensky; Giuliani associates says Ukraine scheme "all about 2020"; Trump still faces GOP challengers for the presidency despite many states cancelling GOP primaries; Buttigieg blitzes Iowa as impeachment trial takes four Senate Democrats off campaign trail; Impeachment trial takes four 2020 Dems off campaign trail; Sanders on impeachment trial: I'd rather be campaigning but I swore an oath; New Buttigieg Ads target Iowa counties Trump flipped; Source: Intel Officials don't want public hearings on worldwide threats after angering Trump last year; Putin's handpicked new PM takes over today after entire government resigns; Putin appears to cement grip on power by changing rules of Russian constitution; 

Rep. Amash reacts to Pelosi's picks for impeachment managers; Yovanovitch wants investigation into "disturbing" surveillance; New letters: Giuliani had Trump's "knowledge and consent" to request meeting with Ukraine president; Klobuchar: there's a double standard for women in politics, but I can win presidency; Warren-Sanders feud takes center stage at CNN debate; Biden & Sanders spar over Iraq war vote during CNN debate; Candidates make final cases to Iowa voters during CNN debate; WH undecided on including Trump defenders in trial; Trump signs first phase of trade deal with China on the same day house delivers impeachment articles; Dow closes about 29k for first time as Trump signs phase one of trade deal with China; Any moment: Pelosi to sign article of impeachment;

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 is at it again, trying to help Trump; Biden Campaign: Hack proves Putin & Trump see Biden as threat; Pelosi demands Trump Admin brief Congress on Burisma hack; 

Trump: WH has been consistent on threats from Iran; Trump officials struggle to defend claims of embassy plots; Esper: I saw no evidence of threats against four embassies; Iran accused of shooting protesters demonstrating against regime; Protesters in Iran call for regime's top leaders to step down; Pompeo: U.S. Strike on Iran's top general was part of a "bigger strategy"; Trump shares photoshopped image of Pelosi & Schumer wearing traditional Islamic clothing in front of Iran flag; Pelosi preps to hand over articles as reps still in dark over impeachment manager selection, Pelosi accusing McConnell of a "cover up"; McConnell blasts Pelosi for "weak impeachment case, says he's glad Pelosi realized she never had any "leverage"; GOP senator asks Trump to "not infect" trial with house reps; White House wants senate to be able to dismiss Trump charges; Pelosi: Senate must call witnesses or "pay a price"; Sen Collins and small group of GOP senators working on agreement to call impeachment witnesses; Schiff: we are considering subpoenaing Bolton; Trump: if senate holds impeachment trial, it gives dems credit; Candidates prepare for final debate before Iowa caucuses; Sources: Sanders told Warren in 2018 private meeting that a woman can't win; Sanders: "ludicrous" to believe I said that; Sanders slams Biden's Iraq war vote, Kerry says he's "distorting" Biden's record; Poll: Biden holds strong lead among African-American voters; Impeachment trial's impact on presidential campaigns; Cory Booker drops out of presidential race; Bloomberg: Dems in danger of repeating 2016; AG Barr on Pensacola attack: "this was an act of terrorism"; U.S. sending 21 Saudi cadets home after shooting; Australia drops carrots & sweet potatoes to starving wildlife