I can only site an article in la Gazzetta dello Sport yesterday which published Ivan Basso's blood values during the Giro. His hematocrit levels were 43% at the start, 39% after Zoncolan and 38.something at the end of the race.
The daily said this was within "normal human parameter's" and hence, for it, was evidence of Basso being clean throughout the event.
Then there would be Aldo Sassi's sworn testimony that his "boys" (Basso, Evans, and a few other top riders) are clean as he wouldn't tollerate anything less and only works with those whom he believes to be sincere.
Does that mean I believe Basso won the Giro clean? No. However it does seem to me that the risks he would be taking, after his involvement with OP and consequent ban, of defrauding the sport and its fans again would indeed be so great that he would be unbelievably stupid and heinous to engage in doping at this point of his career. I also believe Sassi is sincere in his statements.
Does this, then, mean I have know doubts about Basso's performance? No.
Let's just say I concede myself a little cautious optimism and would find it more incredible that he would be doping now, than accepting a clean Giro win. Though this not without some considerable dilemma. How else can one look upon the sport in this regard?