"...the unauthorized disclosure of this effort damages... national security..."

Today's Presidential radio address simply nails it:

...Yesterday the existence of this secret program was revealed in media reports, after being improperly provided to news organizations. As a result, our enemies have learned information they should not have, and the unauthorized disclosure of this effort damages our national security and puts our citizens at risk. Revealing classified information is illegal, alerts our enemies, and endangers our country. As the 9/11 Commission pointed out, it was clear that terrorists inside the United States were communicating with terrorists abroad before the September the 11th attacks, and the commission criticized our nation's inability to uncover links between terrorists here at home and terrorists abroad...

The Defeatocrats, as usual, end up on the wrong side of history. First they criticize the President for not following the 9/11 Commission's dictates. Now they pillory the administration for following the commission's recommendations. But that's typical of their divided party, which can't reach consensus on anything important, least of all the war on terror.

By the way, you have to get about fifty paragraphs into the original New York Times article to read this little gem:

...[In 2002,] Justice Department lawyers disclosed their thinking on the issue of warrantless wiretaps in national security cases in a ... brief... [which said] that "the Constitution vests in the President inherent authority to conduct warrantless intelligence surveillance (electronic or otherwise) of foreign powers or their agents, and Congress cannot by statute extinguish that constitutional authority."

In other words, the practice was considered by the Justice Department and ruled legal.