Anderson Cooper 360

Key Trump Congressional Allies In Secure Impeachment Hearings Coordinating With White House On Witness Disclosures; Source: Vindman Testified White House Lawyer Told Him Not To Talk About Pres. Trump's Ukraine Call; President Trump's House Allies Claim "We Have Tried To Abide By Rules" Amid News They're Coordinating Witness Fallout With WH; Beto O'Rourke Drops Out Of 2020 Race; Wash. Post: Growing Number Of GOP Senators Consider Acknowledging Pres. Trump's Quid Pro Quo On Ukraine; NY Times/Siena College Poll: Warren Leads Tight Iowa Race As Biden Fades; On The Front Line; What The War Between Ukraine And Russia Looks Like; Ukraine Feels Repercussions Of Frozen U.S. Military Aid On The Battlefield via Knit