He didn't show up.
Here's the letter from chairman Patrick Leahy and ranking member Arlen Specter to Gonzales, which includes this paragraph:
You ignored the subpoena, did not come forward today, did not produce the documents and did not even offer an explanation for your noncompliance. Your action today is in defiance of the Committee’s subpoena without explanation of any legal basis for doing so.Hasn't the Bush administration already made it abundantly clear that it does not consider itself bound by the rule of law?
UPDATE: The Department of Justice has responded to the subpoena by producing a single Karl Rove email sent on February 28, 2007.