[flitton]

Difficult to know which one is his agenda. This case has by this account a year or so to run. OK it's a slow news cycle now but I can't see why he would raise this now?
There doesn't seem any obvious advantage in the timing, surely if he wants to return to the Senate with a bang he'd be better saying this early next year.
If it's anti-Hillary perhaps there's some behind the scenes maoeuvering that will come out soon.
Actually I've just thought it's possible he has a source and some juicy evidence is coming out soon.

[Phsstpok]

I don't think it's his play, so the timing isn't his to control.

I think he's been informed that others are beginning a campaign (MoveOn.ORG?) and he's trying to get out in front of it. After all, he has claimed credit for running "aggressive investigations" of BCCI (where he covered up Clark Clifford and other Democrat's roles) and he can't allow something new, whether new evidence or just a new smear campaign, to spill over and damage him.

This may be preemptive, as you suggest.