Did Bush break the law?

Perhaps. But the person or persons who leaked the news to the NYT almost certainly did.

These "concerned" officials have acted extremely unprofessionally: they clearly violated their secrecy oath and the provisions of the 1980 Classified Information Procedures Act by providing classified information to the media. While it may come as a shock to some, the media is NOT entitled to classified information under any circumstances.

Wretchard looks back to a time when it was unthinkable to leak such intelligence.

Once upon a time signals intelligence was considered so important that considerable efforts were taken to prevent its compromise. Captain John Philip Cromwell, who was privy to the secrets of signals intelligence, elected to go down with the USS Sculpin rather than risk capture by the Japanese and reveal his knowledge under torture. Cromwell agonized over a problem the NYT editorial board might have found easier to resolve.

James Joyner suspects that there's more to the story than wiretapping.

The facts that AG Gonzales has dubbed this "probably the most classified program that exists in the United States government" and that the NYT held onto the story for over a year and then removed certain "technical details" also speaks to the likelihood that this program involved some cutting edge technologies that the government would just as soon not have our enemies know about.