the election process. joining me now is nbc's intelligence and national security's correspondent ken dilanian. thank you for being here again. donald trump consistently questioned reports the russians are behind the hacks. how does intelligence prove it was, in fact, russia? >> we don't completely know the answer to that, melissa. it's probably a good thing we don't, because it involves sensitive sources and methods, but it was interesting to hear president obama say yesterday he expects the american public to take the intelligence community at its word about this. i can relate. i talk to these people a lot. they are patriotic americans and non-political bought whole cadre of people who aren't willing to accept this intelligence and at some point there has to be a measure of proof offered. it's difficult to do. we're talking sensitive sources and methods. again, human agents who risk their lives to give information to intelligence officers or communications intercepts. for example, if they have an e-mail or phone call they've