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

WASHINGTON, March 16, 2012— -- After sweeping Tuesday's southern primaries, Republican presidential candidate Rick Santorum comes to "This Week" on Sunday.

With close wins in Alabama and Mississippi solidifying his position as Mitt Romney's main challenger, can Santorum keep the momentum going in Illinois next week? Can he overcome Romney's delegate advantage and force a showdown for the nomination at the Republican convention in Tampa? And will he be able to take on President Obama?

ABC News senior political correspondent Jonathan Karl goes one-on-one with Rick Santorum, Sunday on "This Week."

Plus, our powerhouse roundtable with ABC's George Will, former Mississippi Governor Haley Barbour, Priorities USA co-founder Bill Burton, Washington Post national political reporter Nia-Malika Henderson, and Washington Post columnist and associate editor David Ignatius debates all the week's politics.

Would a brokered GOP convention damage the eventual nominee? Will promising news on jobs and retail sales help President Obama overcome his low poll numbers? Will the deadly massacre in Afghanistan accelerate the U.S. withdrawal strategy?

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