Will the new stories hurt Bush? Time will tell! But this is how I am slicing that into bite-sized questions:
Both sides are trying to do three things - rally the base, convert undecideds, and raise money from donors. Do these new stories energize the Fahrenheit 911 crowd? Probably not. Do they discourage the Reps, or their donors? Not immediately - what will discourage them (OK, me) is a weak, confused White House response.
Karl Rove can actually use these stories to his advantage. First, spin it as a last gasp, say-anything attempt by the media to win this for their guy Kerry. (Waddya mean, "spin"?). This will rally a newly-aggrieved base.
Secondly (and here comes your sound-bite), turn the AWOL story back on Kerry. "The President is running on his record of leadership and his vision for a safer, more propserous America. We are only having this discussion about new documents because the President has signed the Form 180 authorizing the release of all of his records.
The President is not running on a service record he has nontheless fully disclosed; John Kerry is running on a service record he has not fully disclosed.. If we are going to compare the two candidates' records, we need full disclosure from both sides." (See "MORE", below).
Finally, timing is everything - the Kitty Kelley book, coupled with the new AWOL charges, looks like a liberal media mudslide, and increases the effectiveness of the "this is a say-anything assault by the media" meme.
Time will tell. But Karl has plenty of cards, and we assume he saw this coming. An effective response will nicely highlight Bush's ability to put together an effective team, and contrast well with Kerry's August floundering.
UPDATE: Tim Graham corners Kurtz's Kitty Kelley coverage.