THE REAL REASON THE NYSLIMES BROKE THE STORY WAS TO GET MICHELLE “FINALLY PROUD” OBAMA OFF THE FRONT PAGE. it worked!
I think that was an added benefit to the timing but the main priority was to muddy the water as early as possible after the nomination seemed statistically secure. Who knows? The timing and the lack of any real evidence a month after endorsing McCain seems so...obvious as to their overall motive.
The NYT claims that they were not satisfied with the story until Tuesday. My question to the NYT would be "what were the final pieces that fell into place within the last few days that allowed you to feel confident the story was ready to go to press?" They can't answer that because the story had been long since completed and it was just a question of when to drop the smear.