Stop asking it, and start
asserting it. On every news outlet, Democrats should lay out the bottom line:
"Karl Rove told reporters that Joe Wilson's wife worked for the CIA. Calls were made from Air Force One telling reporters that Joe Wilson's wife worked for the CIA. And from day one, President Bush has refused to do anything about the top aides who gave out this information."
If asked to prove it, take the opportunity to lay out the case. But that's just the icing on the cake -- the point, as Lyndon Johnson (or whoever) supposedly said, is to make the charge ... and if the Bushites don't like it, force them to deny it. Either way, the message gets out to the public.
(These thoughts expressed with a typically verbose preamble at Needlenose.)