Former State Department official on Bill Taylor's testimony
In his testimony Tuesday, top U.S. diplomat to Ukraine Bill Taylor described what he saw as two separate channels for communication with the country: one that he led, and another that was "highly irregular" and spearheaded in part by President Trump's personal attorney Rudy Giuliani. Former Deputy Assistant Secretary of State Glen Johnson joins CBSN's "Red & Blue" to explain how the lines of diplomacy are supposed to work.