Republican Presidential candidate Rick Santorum is 'all in' in Iowa. He'd been to every corner of the state. He's working hard to rise to the top, and after a key endorsement he says he's gaining traction. But does he have enough time to spoil the party?

Then Former U.S. Congressman Bob Walker, a Gingrich supporter and Former NH Governor John Sununu, a Romney supporter, explain why their guy will go the distance.

Then, extending the payroll tax cut and unemployment benefits; they are set to expire at the end of the year. Will either side blink? And who will get the blame when voters go to the ballots in the fall? We ask former Obama White House Communications Director Anita Dunn and Republican Tom Davis a former member of congress.

Finally, after announcing massive cuts to its service – What’s the future of the USPS? Postmaster general and CEO, Patrick Donahoe joins us for an exclusive interview.

It’s all this Sunday on State of the Union with Candy Crowley at 9 a.m. and 12 p.m. ET