President Trump not expected to try to block Comey testimony, aides say

The president has no plan to invoke executive privilege.

“There’s nothing Comey could say that would be more damaging than trying to silence him," one White House adviser told ABC News.

Another official said it is questionable whether it would even work to invoke executive privilege to prevent the former FBI chief from testifying about his conversations with the president before Trump fired him considering that Comey is now a private citizen and Trump himself has in tweets and interviews discussed details of his private talks with him.

The executive privilege doctrine is “the right of a president to withhold information from those with compulsory power -- including special counsels and congressional committees -- but only when it’s in the public interest to do so,” said Mark Rozell, dean of the Schar School of Policy and Government at George Mason University and author of "Executive Privilege: Presidential Power, Secrecy and Accountability."

ABC's Alexander Mallin and Lauren Pearle contributed reporting to this piece.