Brett McGurk former Special Envoy for Coalition Fighting Isis and now National Security Council's coordinator for the Middle East and North Africa. He explains how Turkey helped Isis to grow.
Brett H. McGurk is an American diplomat, attorney, and academic who served in senior national security positions under presidents George W. Bush, Barack Obama, and Donald Trump. He was the Special Presidential Envoy for the Global Coalition to Counter ISIL
"I ran the Isis campaign.
40,000 foreign fighters, jihadis from 110 countries around the world all came into Syria to fight in that war and they all came through Turkey. The caliphate is on the border of Turkey we worked with Turkey. I was in Turkey more than any other country to have them seal their border and they would not do it.
They said they couldn't do it, but the minute the Kurds took parts of the border, they totally sealed with a wall."