more intense on facebook. set to clamp down on online interference ahead of the 2020 election. lester holt sat down with mark zuckerberg who admits the company was caught on its back foot in 2016 but zuckerberg says they have no safeguards to fight interference. when it comes to potential disinformation from actors at home zuckerberg seems to be on defense. >> do you feel like you're giving a green light to politicians that -- >> no, look -- >> lie, lie, lie. >> i believe that it is important for people to be able to hear and see what politicians are saying. i think that when they do that that speech will be heavily scrutinized by other journalists, by other people. >> nbc's jo ling kent, zuckerberg seemed to get fired up on that point. >> reporter: what zuckerberg is referencing is the company's