The Republican presidential hopefuls spent their New Year's weekend trying to  differentiate themselves  from each other and convince Iowans to caucus for them on Tuesday. Front-runner Mitt Romney tried to fend off a new challenge from Rick Santorum, who has surged in recent days to the top of the polls. Ron Paul, who spent his New Year at home in Texas, also stands to make a strong showing in Tuesday's caucuses. The Democratic Party has stepped up efforts in Iowa as well, targeting Romney for his record of laying off workers while CEO of private equity firm Bain Capital. Anna Sale, reporter for It's A Free Country, WNYC's politics website, has the latest developments from on the ground in Iowa. Glenn Thrush, senior White House reporter for Politico, looks at how the Obama campaign is counterattacking the Republicans.