On this week's episode of Tying it Together, Dr. Bruce Jentleson joins host Tim Boyum to explain the story behind all the foreign policy battles garnering the attention of President Trump — from Iran, Venezuela, Ukraine, to Greenland.

Jentleson is a professor at the Sanford School of Public Policy at Duke University.

He's a former senior adviser at the State Department under the Obama and Clinton administrations. He also served as a senior foreign policy advisor to the Al Gore presidential campaign and lectures around the world on foreign policy.