Nobody is sure, it it appears to be his close relationship with Gary Condit, and their joint activities together....(Condit had a fun palace......er.... Condominium)
I think he was told certain facts that would be likely made public if he did not relinquish his seat.
That's the rumor anyway............
Thanks for that info. Explains the holier than thou attitude. No doubt linked with the hope none of this comes out.