Michael Flynn’s plea deal with special counsel Robert Mueller now has congressional investigators hoping they can interview the former national security adviser soon. But such a deal presents a complicated set of pros and cons to both Flynn and Mueller.

Within hours of the deal being entered at a federal courthouse, the ranking Democrat on the House Intelligence Committee was already extending an invitation of sorts to Flynn.

“I have to say, there’s a lot more to come, and the fact that the sentencing has been put off three months will give Bob Mueller a chance to see just what kind of cooperation he can get from Mike Flynn,” Rep. Adam Schiff, D-Calif., said on MSNBC. “And as an investigator in the House, I have to hope that that agreement extends to us as well, that we ought to get his cooperation also.”

Patrick Cotter is a former assistant U.S. attorney, known for his work on the federal case that took down mob boss John Gotti, and says the idea of Flynn now working with the committees is unusual, but is certainly made easier now with the plea deal.

“Given that he’s cooperating, it is in his interest, it seems to me, to cooperate with them because he, in essence, gets ‘points’ for ‘the more cooperation, the better the treatment,’” Cotter told the Washington Examiner. “There’s no scenario that I can imagine where he would be further criminally prosecuted in the federal system for any of the related acts.”

The central issue of any future testimony by Flynn to the House or Senate Intelligence committees is whether that questioning would be public, or behind closed doors. Public testimony would likely create instant objections from the Mueller team.

“The Mueller people want to use his information and his cooperation to build their case,” Cotter explained. “And they may not want what he has to say spread all over the press, because it could inhibit their ability to approach other witnesses. Right now the other witnesses that might be approached by the Mueller people don’t know what [Flynn] is saying. And uncertainty is one of the things that sometimes makes people talk.”

Even during the earliest days after the creation of the special counsel was announced by the Justice Department, some members of Congress worried about whether their investigations would be stymied.

“My concern is that we not end up in a place where special counsel doesn't communicate to Congress for months, or years, a decision he's made about the scope of the investigation,” Sen. Chris Coons, D-Del., said in May, after Mueller was appointed.

Cotter, now in private practice with Greensfelder, Hemker & Gale, P.C. in Chicago, says ultimately, all the decision making power rests with Flynn, and Mueller has no legal authority to either compel Flynn to talk to the congressional committees, or to prevent him from talking to them.

“There is good case law out there that says a person, even though they’ve pleaded guilty, they have not given up their Fifth Amendment right to remain silent, because, anything they say in that compelled testimony could, in theory, be used to hurt them.”

Cotter also spoke of the possibility that testimony by Flynn before the committees could reveal state violations of some kind, for which Flynn could still face legal jeopardy.