Notice that he didn't deny that he wrote it.
IF they try to use this in the debates, Bush could use a line similar to what you folks have been saying. Something along the lines of this:
Demrat candidate - "In fact, I have received a memo from inside sources that say**insert intelligence operational news here**about what's been happening in your administration concerning Iraq."
President Bush - "I know exactly which memo you're referring to. I know who wrote it and I have read it. I also know that it was something that was supposed to have been kept inside our intelligence circles. You know: "Top Secret"? It's pretty revealing that you're willing to risk American lives in an attempt to gain the office of the Presidency. Luckily, that memo was false, and we made it easily leakable to certain people, knowing that these certain people were unreliable for keeping our national secrets out of the hands of the enemy. Enemies who are most likely watching this debate. By these actions, you have lost all trust you might've had with the American people, and don't deserve to sit in The Oval Office."