Digby think it is -
" . . . This may be the most important moment of the campaign. Bush's only real strength is the hagiography that was carefully cultivated after the attacks. Without that, they have very little. In fact, he becomes a failure of epic proportions. His entire campaign rests on the idea that Bush handled 9/11 flawlessly.
The press must be pushed on this. I already knew all of this stuff and it seemed very powerful to me. I would hope that the media would feel the heat from this story as well. The Democrats need to get together and push this over the next week, as the testimony at the hearings is highlighted. It is the chink in Bush's codpiece and it's time to administer a deadly blow."
http://digbysblog.blogspot.com/
I think it can be, if Kerry picks up the cudgel and hammers Bush to death with this - starting now.
I ran a poll a few days on what should be Kerry's focus of attack. I'd like to run it again now, to judge the effect of Clakre's appearance tonight.