The longer of Mr. Keller's two prepared statements said the paper initially held the story based on national security considerations and assurances that everyone in government believed the expanded eavesdropping was legal. But when further reporting showed that legal questions loomed larger than The Times first thought and that a story could be written without certain genuinely sensitive technical details, he said, the paper decided to publish. (Mr. Keller's two prepared statements, as well as some thoughtful reader comments, are posted on the Public Editor's Web Journal.)

Times readers would have benefited if the explanation in the original article had simply been expanded to include the points Mr. Keller made after publication. And if the length of that proved too clunky for inclusion in the article, the explanation could have been published as a separate article near the main one. Even the sentence he provided me as to why he would not answer my questions offered some possible insight.

Protection of sources is the most plausible reason I've been able to identify for The Times's woeful explanation in the article and for the silence of Mr. Sulzberger and Mr. Keller. I base this on Mr. Keller's response to me: "There is really no way to have a full discussion of the back story without talking about when and how we knew what we knew, and we can't do that."

Taken at face value, Mr. Keller seems to be contending that the sourcing for the eavesdropping article is so intertwined with the decisions about when and what to publish that a full explanation could risk revealing the sources. I have no trouble accepting the importance of confidential sourcing concerns here. The reporters' nearly one dozen confidential sources enabled them to produce a powerful article that I think served the public interest.

With confidential sourcing under attack and the reporters digging in the backyards of both intelligence and politics, The Times needs to guard the sources for the eavesdropping article with extra special care. Telling readers the time that the reporters got one specific fact, for instance, could turn out to be a dangling thread of information that the White House or the Justice Department could tug at until it leads them to the source. Indeed, word came Friday that the Justice Department has opened an investigation into the disclosure of classified information about the eavesdropping.

The most obvious and troublesome omission in the explanation was the failure to address whether The Times knew about the eavesdropping operation before the Nov. 2, 2004, presidential election. That point was hard to ignore when the explanation in the article referred rather vaguely to having "delayed publication for a year." To me, this language means the article was fully confirmed and ready to publish a year ago -- after perhaps weeks of reporting on the initial tip -- and then was delayed.

Mr. Keller dealt directly with the timing of the initial tip in his later statements. The eavesdropping information "first became known to Times reporters" a year ago, he said. These two different descriptions of the article's status in the general vicinity of Election Day last year leave me puzzled.