POLITICO reporters discuss Senator Flake pulling the plug on his reelection campaign in a dramatic Senate floor speech and what's to come in the second open Senate race in Arizona since 1994. The panel also discusses the 2016 Facebook ads that were placed by a Russian company last year. They’re now the subject of multiple investigations, but there’s an also an effort to close some regulatory loopholes to make sure this doesn’t happen again.Learn more about your ad choices. Visit megaphone.fm/adchoices