WASHINGTON (CNN) -- Word came Wednesday that Washington Post assistant managing editor Bob Woodward, of Watergate fame, knew the name of CIA operative Valerie Plame before it was published in a July 2003 column. The attorney for I. Lewis "Scooter" Libby, Vice President Dick Cheney's former chief of staff and the only person indicted during the CIA leak investigation, quickly asserted that Woodward's admission undermined the case against his client.As questions also percolated about the Post's ace, the paper reported that Woodward had issued an apology to Executive Editor Leonard Downie Jr. for not sharing the information sooner. CNN's Wolf Blitzer had an opportunity to chat with Downie about what Woodward knew, his testimony before a grand jury and his future at the Post.BLITZER: What did (Woodward) say to you when you called him about that so-called bombshell?DOWNIE: Well, he did not have a bombshell in the sense of a story, Wolf. We did not have a story to put in the Post. That exchange took place on television, after he had first told me, in late October, about the fact that he had had this conversation back in June of 2003.It was a very brief part of a much longer interview that Bob was conducting for his book with a source that he had conducted many interviews with for his book. And at the time, he doesn't think it was very important. And it was a kind of byplay that wasn't even part of the interview that he was conducting.So he didn't have a bombshell that he could put in the newspaper when he was talking on television recently. But what he should have done during the intervening time after June of 2003 was still tell me that he'd had this discussion with this source.I'm not sure we could have done anything with it because it was a confidential conversation with a confidential source. I'm not sure we could have storified it anyway. But it's a conversation that we should have had so we could make a decision about how to proceed.And as a result of the conversations we've had since then, Bob has acknowledged today that he made a mistake in not telling me about it sooner. He's apologized to me and to the newspaper. And we're going to move along from here now and work on other reporting of his in the future.BLITZER: What made him come forward and finally tell you, some two years after the fact?DOWNIE: It was getting near the time when the grand jury was about to expire. We were all expecting that the special prosecutor was going to take some kind of action. And the events that were going on reminded Bob that probably he should tell me about this.BLITZER: Why didn't you immediately inform your readers, when he told you, yes, he had learned about this early on, long before, you know, Bob Novak wrote his column in July of 2003? Why not, without revealing the source, at least tell your readers what's going on?DOWNIE: Because the source didn't allow us to. The source was insisting on maintaining the confidentiality of this particular part of his interviews with Bob -- and the rest of these interviews with Bob, for that matter. So we didn't have something we could report at that time.BLITZER: You could have revealed to your readers that an unnamed source had told Bob Woodward about this two years earlier without naming the source.DOWNIE: At that point, once Bob had told me about this, then a chain of events took place that led to his being asked by the special prosecutor to testify in a deposition, which Bob did on Monday.And we then set about trying to get releases from sources for the purposes of that testimony, and also for the purposes of our journalism. And two of those sources released us from that. We've now named them, one in the newspaper today, one in the newspaper tomorrow. But this particular source still had not released us from that pledge, so we were not able to report that.BLITZER: There were some days, though, that you could have. You're saying that this happened before October 28, the day the grand jury expired. That was the day that Scooter Libby was indicted. He came to you a few days earlier. It wasn't until November 3 that this source came to the prosecutor, to Patrick Fitzgerald, and said, "I did have a conversation with Bob Woodward." So there was a period of a week, at least, I'm guessing, that this information could have been disclosed.DOWNIE: During which time we were still under the confidentiality pledge, as we are as I sit here talking to you right now. That this is a confidential source who does not want us to report on this information. And we're still unable to. We must maintain the sanctity of these source relationships.BLITZER: He says in a statement, Bob Woodward, "I apologize because I should have told him," referring to you, "about this much sooner. I explained in detail that I was trying to protect my sources. That's job No. 1 in a case like this. I hunkered down. I'm in the habit of keeping secrets. I didn't want anything out there that was going to get me subpoenaed." Does he owe, or do you owe, the readers of The Washington Post an apology?DOWNIE: No. Bob owed me and the newspaper an apology for not telling me, but if he had told me, I don't know what we would have been able to publish in the newspaper because of the confidential agreement under which this was stated. And we still aren't able to publish the details. We're eager to. We're eager to be freed from that pledge.We are publishing everything that we know about his encounters with the other two sources in which he did not claim Mrs. Wilson's -- the name did not come up. But we're still under an obligation to protect the confidentiality of this source and the information that this source supplied.We've asked to be freed from that pledge. We have not been. We must, as Bob said in the quote that you just gave me -- the sanctity of these pledges of confidentiality are essential to the kind of reporting that Bob does, the kind of reports that's kept our readers so well informed for many years now, over three decades, in which Bob has revealed the inner workings of what's going on in many governments, broken many important stories, beginning with Watergate, continuing on through 9/11, would not be possible without this source relationship and without him keeping his promises.He kept his promise about Deep Throat for three decades, even to the point that somebody else revealed that information, and Bob was unable to. And that, those types of promises, we're going to have to continue to keep.BLITZER: The thought that Bob Woodward, having kept the Deep Throat source secret for so many decades, actually goes forward and talks about sources before a prosecutor. That thought, in and of itself, is pretty shocking. But you say two of the sources have been released. He spoke with three administration officials. Now, one of them was, what, the White House chief of staff?DOWNIE: Yes, the White House chief of staff Andy Card today said that we are free to report on this conversation that Woodward testified about. I have to go back to correct something you just said, Wolf. You said that after keeping the secret about Deep Throat for all these years he then gave this deposition to the special prosecutor.He did so only after all three sources, including the source's name we can't divulge in the newspaper, released him from his pledge of confidentiality for the purposes of that deposition. So he was not violating the source relationship in giving that deposition. Otherwise, he wouldn't have done so.BLITZER: What was the nature of the conversation with the White House chief of staff Andy Card?DOWNIE: This did not come up. It was an incidental conversation about something else, and the special prosecutor merely wanted to know from Bob, did the subject of Valerie Plame come up, and Bob said no.BLITZER: Who is the second official you're about to name in The Washington Post?DOWNIE: That is Andy Card. Today we already named Libby and discussed Bob's testimony about his conversation with Libby in which Bob also does not remember Valerie Plame coming up, and as he searched through his notes, did not see any notes that he had taken about Valerie Plame being named by Mr. Libby.BLITZER: And so the third source, who still doesn't want his or her name to be made public, Bob did discuss the conversation with this third still-unnamed source in detail with the special prosecutor?DOWNIE: Yes, because the source gave Bob permission to discuss this with the special prosecutor, but not permission to write about it in the Post.BLITZER: Can you report, can Bob report, or The Washington Post report, the nature of this conversation with this third unidentified source without violating any kind of ground rules? Now that he's discussed it in a deposition that will be presented, presumably, to a grand jury?DOWNIE: No. That secret testimony will be presented secretly to the grand jury. We must still maintain this pledge to our source. If you recall, much earlier in the investigation, another one of our reporters, Walter Pincus, testified in a deposition also, with permission of the source, about a conversation which turns out that Mrs. Wilson didn't come up.But nevertheless, that source gave permission for Walter to testify, but not permission for Walter to write about the details of the conversation or identify the source, and we still haven't. It is sacred at this newspaper, as it is at most newspapers, and I assume at your network also, to not reveal the names and contents of conversations unless we're given permission to do so by our confidential sources.BLITZER: Are you angry at Bob Woodward?DOWNIE: No. He made a mistake. He apologized for it. I've asked him to improve his communications with me about work he's doing on his books that could produce things for the newspaper. He's promised to do so. We're going to move ahead now.BLITZER: And so, unlike Judy Miller, whose career at The New York Times is over with, you expect Bob Woodward to be at The Washington Post for a long time to come?DOWNIE: Oh, yes. I certainly do. This is not an analogous case at all.