Transcript for US troops withdraw from Syria

tonight, new fallout coming in late da after surprise decision from president trump, ordering the withdrawal of all U.S. Troops from Syria, saying the war againstsis has be N. But night, even some key repuan say this is a very dangerous move. Here ABC's chief global affair corredent Martha Raddatz tonight. Reporte today, president trump alt declaring mission mpitdden decision to pull all 2,000 American troops out of Syria within the next 30 days. The prentweeting, "We have defeaisa, nly reasonor being there." The move flies in the face of what many of his own advisers on Syria were saying just Dago. 'Ve learned one thing over the years, enduring defeat of a group like this, meansou cat just defeat their physical space and leave. You have to mar internal security forces are in place to ensatcurity gaire endurin As far as stazation, we stl have a LG Reporter: As a candidate, Donald Trump said the decision to withdraw U.S. Troopfrom aq in 2011 C a vacuum for ISIS to fill. I opposed the rs way Obama, Clinton left Iraq. Reporter: Now, some of T president's strongest allies say he is makingame mistake himself with Syria. If this decision is a withdral ol of our forces in Syria now, we're dramatically Leafe. Is an obaikhiosl, in my mind, mistake. A gre error. T defeated So, let's get to Marth Raddatz, who has been covering thoryears. And Martha, Republican leaders were blindsided by thistonight. Lindsey graham calling it a big fo ISIS. Reporter: That's right,david. ISIS has L almost all of its territy, but 000 fighters remain, there are concern going forward a intelligence. Good informiodavid? Raddatz with us from the washingtoneautonight. Martha, thank you.

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