Robert Novak writes:

Special Prosecutor Patrick Fitzgerald has informed my attorneys that, after two and one-half years, his investigation of the CIA leak case concerning matters directly relating to me has been concluded. That frees me to reveal my role in the federal inquiry that, at the request of Fitzgerald, I have kept secret.
I have cooperated in the investigation while trying to protect journalistic privileges under the First Amendment and shield sources who have not revealed themselves. I have been subpoenaed by and testified to a federal grand jury. Published reports that I took the Fifth Amendment, made a plea bargain with the prosecutors or was a prosecutorial target were all untrue.
For nearly the entire time of his investigation, Fitzgerald knew — independent of me — the identity of the sources I used in my column of July 14, 2003. A federal investigation was triggered when I reported that former Ambassador Joseph Wilson’s wife, Valerie Plame Wilson, was employed by the CIA and helped initiate his 2002 mission to Niger. That Fitzgerald did not indict any of these sources may indicate his conclusion that none of them violated the Intelligence Identities Protection Act.
…I have promised to discuss my role in the investigation when permitted by the prosecution, and I do so now.
The news broke Sept. 26, 2003, that the Justice Department was investigating the CIA leak case…
The FBI soon asked to interview me, prompting my first major decision. My attorneys advised me that I had no certain constitutional basis to refuse cooperation if subpoenaed by a grand jury…
I was interrogated at the Swidler Berlin offices Oct. 7, 2003, by an FBI inspector and two agents. I had not identified my sources to my attorneys, and I told them I would not reveal them to the FBI. I did disclose how Valerie Wilson’s role was reported to me, but the FBI did not press me to disclose my sources.
On Dec. 30, 2003, the Justice Department named Fitzgerald as special prosecutor. An appointment was made for Fitzgerald to interview me at Swidler Berlin on Jan. 14, 2004. The problem facing me was that the special prosecutor had obtained signed waivers from every official who might have given me information about Wilson’s wife.
That created a dilemma. I did not believe blanket waivers in any way relieved me of my journalistic responsibility to protect a source…
However, on Jan. 12, two days before my meeting with Fitzgerald, the special prosecutor informed Hamilton that he would be bringing to the Swidler Berlin offices only two waivers. One was by my principal source in the Valerie Wilson column, a source whose name has not yet been revealed. The other was by presidential adviser Karl Rove, whom I interpret as confirming my primary source’s information. In other words, the special prosecutor knew the names of my sources.
When Fitzgerald arrived, he had a third waiver in hand — from Bill Harlow, the CIA public information officer who was my CIA source for the column confirming Mrs. Wilson’s identity. I answered questions using the names of Rove, Harlow and my primary source.
I had a second session with Fitzgerald at Swidler Berlin on Feb. 5, 2004, after which I was subpoenaed to appear before the grand jury. I testified there at the U.S. courthouse in Washington on Feb. 25.
In these four appearances with federal authorities, I declined to answer when the questioning touched on matters beyond the CIA leak case…
I have revealed Rove’s name because his attorney has divulged the substance of our conversation, though in a form different from my recollection. I have revealed Harlow’s name because he has publicly disclosed his version of our conversation, which also differs from my recollection. My primary source has not come forward to identify himself…
In my sworn testimony, I said what I have contended in my columns and on television: Joe Wilson’s wife’s role in instituting her husband’s mission was revealed to me in the middle of a long interview with an official who I have previously said was not a political gunslinger. After the federal investigation was announced, he told me through a third party that the disclosure was inadvertent on his part.
Following my interview with the primary source, I sought out the second administration official and the CIA spokesman for confirmation. I learned Valerie Plame’s name from Joe Wilson’s entry in “Who’s Who in America.”
I considered his wife’s role in initiating Wilson’s mission, later confirmed by the Senate Intelligence Committee, to be a previously undisclosed part of an important news story. I reported it on that basis.