What challenges lie ahead for a permanent fix in Iran?

Aired: 1/13/2014 | 0:04:46 | Clip
The U.S. and Iran have finally settled on the details of an interim nuclear deal, with talks for a final agreement slated for February. Gwen Ifill talks to chief foreign correspondent Margaret Warner about diplomatic relations going forward with Iran, including the Syrian peace efforts and pressure on Capitol Hill for sanctions.