If Hillary is behind this and wanting to get on the ticket, she has to be careful. She cannot allow too much disarray in the Party before Kerry removes himself because there wouldn't be time to pull the Party back together.
Yet, she can't act too quickly, as a lengthy (still 3 months) campaign period opens HER up to too much scrutiny.
She needs to let Kerry float into late Sept, at least, or continue to sink his ship and have her sights on 2008.
That echos my thoughts...