UCLA Professor Mark Kleiman is happy to point out that Rove may have met the statutory requirements for espionage:
But Rove’s conduct certainly meets the far less demanding elements of the Espionage Act: (1) possession of (2) information (3) relating to the national defense (4) which the person possessing it has reason to know could be used to damage the United States or aid a foreign nation and (5) wilful communication of that information to (6) a person not entitled to receive it.
Under the Espionage Act, the person doing the communicating need not actually know that revelation could be damaging; he needs only "reason to know." Classification is generally reason to know, and a security-clearance holder is responsible for knowing what information is classified.
Nor is it necessary that the discloser intend public distribution; if Rove told Cooper—which he did—and Cooper didn’t have a security clearance—which he didn’t—the crime would have been complete.
And to be a crime the disclosure need not be intended to damage the national security; it is only the act of communication itself that must be wilful.
It’s also a crime to "cause" such information to be communicated, for example by asking someone else to do so.
I haven’t checked him on this, but it is interesting to consider.