>> i encountered an irregular informal channel of u.s. policymaking with respect to ukraine. unaccountable to congress, a channel that included then special envoy kurt volker, u.s. ambassador to the european union gordon sondland, secretary of energy rick perry, white house chief of staff mick mulvaney, and as i subsequently learned mr. giuliani. the odd push to make president zelensky publicly commit to investigations of burisma and alleged interference in the 2016 election showed how the official foreign policy of the united states was undercut by the irregular efforts led by mr. giuliani. >> reporter: he testified alongside deputy assistant secretary of state george kent who also found rudy giuliani's actions in ukraine deeply troubling. >> what interests do you believe he was promoting, mr. kent? >> i believe he was looking to dig up political dirt against a potential rival in the next election cycle. >> i agree with mr. kent.