opportunity for the american people to evaluate the witnesses for themselves and make their own determinations about the credibility of the witnesses. >> reporter: up first, wednesday, the most senior u.s. diplomat in ukraine, ambassador bill taylor and his boss george kent followed friday by ambassador marie yovanovitch whom the president pulled out of ukraine after what she called a concerted campaign against her by rudy giuliani and others. all three have testified to the shadow ukraine policy that giuliani was leading on behalf of president trump. >> trying to put a ribbon on a sham process doesn't make it any less of a sham. >> reporter: republicans have slammed the process for the secrecy and now they're allowed to call witnesses but democrats have the final say. one big request from republicans, the whistle-blower. >> it is impossible to bring this case forward, in my view fairly, without us knowing who the whistle-blower is and having a chance to cross-examine them. >> reporter: but house intelligence committee chairman adam schiff rejecting that