Katty Kay: Is Trump Going to Try and Stop Comey from Testifying?

EXCERPT:

KAY: "Are we all convinced that he’s going to be able to speak out, that the White House is not going to intervene in some way and try to stop his — they won’t be able to?" 
HALPERIN: "It would bring government to a halt if they tried to stop him." 
ROBINSON: "They could claim executive privilege." 
KAY: "That’s what I’m wondering." 
SCARBOROUGH: "Trump has probably waived executive privilege by talking about the conversation so much himself." 
KAY: "You know they’re sitting, having these conversations in the White House trying to figure out if they can actually do that."