Today's discussions:Former US attorney Chuck Rosenberg, former undersecretary of State Rick Stengel, MSNBC contributor Karine Jean-Pierre, former assistant director of the FBI Frank Figliuzzi, and NYT's Nick Confessore and Adam Goldman on former acting FBI director Andrew McCabe breaking his silence after he was fired with a warning to the president;Author of "Parkland" and "Columbine" Dave Cullen joins Nicolle Wallace to discuss the progress on gun control one year after the tragic shooting in Parkland, Florida;Former US attorney Chuck Rosenberg, former undersecretary of State Rick Stengel, MSNBC contributor Karine Jean-Pierre, and NYT's Nick Confessore and Adam Goldman on former acting FBI director Andrew McCabe breaking his silence;NYT's Peter Baker, WaPo's Aaron Blake, former US attorney Chuck Rosenberg, former undersecretary of State Rick Stengel, MSNBC contributor Karine Jean-Pierre, and NYT's Nick Confessore on Trump's decision to sign Congress's bill to avoid a shutdown, while also declaring a national emergency to build his wall.