national security team clearly wants the world to know they are taking this seriously. >> we acknowledge the threat. it is real. it is continuing. and we're doing everything we can to have a legitimate election. >> reporter: the president insists he raised the issue in his one-on-one meeting with putin. but 17 days later, his top intelligence adviser, who should know what was discussed, acknowledged he's still not sure. >> i'm not in a position to either understand fully or talk about what happened in helsinki. >> reporter: the president now insists he accepts the intelligence agency's conclusio thinks others may have done it, too. has there been any evidence from the intelligence community that there were others besides russia that were involved in election meddling? >> certainly we know there are others, and we know that there are others that are considering making attempts in 2018. >> reporter: who were the others that were involved in interference in 2016?