♪ liberty. liberty. liberty. liberty. ♪ >> facebook ceo mark zuckerberg is getting slammed by congress for not doing enough to prevent foreign interference in the election. and facebook is learning hard lessons. >> on 2016 we were on your back foot in terms of prevent russia for attempting to interfere in our election. we've spent at lo of -- lot of the last few years, frankly governments, too, from foreign interference. this monday we proactively identified a network of fake russian accounts and a few networks of iranian fake