Coming Up on 'This Week': GOP Candidate Rick Santorum

WASHINGTON, Jan. 20, 2012— -- Just hours after the dust settles on a close Republican primary contest in South Carolina, George Stephanopoulos goes one-on-one with top-contender Rick Santorum, as he vies to derail Mitt Romney from locking up the GOP presidential nomination.

The final vote count shows Santorum edged out Romney in Iowa, and he's now taking on the presumptive front-runner with a scathing ad blitz, while launching fresh attacks on Newt Gingrich's suitability for office.

As Texas Gov. Rick Perry leaves the race and Newt Gingrich rides a late surge, can Santorum gain ground in the first Southern primary? And can he still find a path to the GOP nomination?

See former Pennsylvania Senator Rick Santorum this Sunday, only on "This Week."

Plus, our powerhouse roundtable with ABC's George Will, political strategist and ABC News analyst Matthew Dowd, National Journal's Ron Brownstein, and The Nation's Katrina vanden Heuvel debate the quickly-changing primary landscape, and whether the race for the nomination is just beginning.

And as President Obama prepares for his State of the Union address next week, which GOP candidate can convince voters he's best suited to take on the president in the general election?

See the whole political picture, Sunday on "This Week with George Stephanopoulos."