His hardline views on abortion and divorce have made him a favourite of Republican conservatives, helping him come within a whisker of winning the Iowa caucus.
But Rick Santorum has a skeleton in the family cupboard -- he comes from a long line of communists and socialists.
The presidential hopeful's relations, who come from the picturesque town of Riva del Garda, on the shores of Lake Garda in Italy, have been left aghast by some of his views on same-sex marriage, welfare and immigration.
"There are Santorums who would be turning in their graves," one cousin told 'Oggi', a weekly news magazine. The Santorums of Italy were "dyed-in-the-wool Reds" with strong links to the Socialist and Communist movements, particularly during the rise of Mussolini.
Their left-wing leanings were well known in Riva del Garda. "Rick's grandfather, Pietro, ran the local post office and had strong liberal convictions," said Maria Malacarne Santorum, whose late husband was a cousin of the former Pennsylvania senator.
"Back in the 1920s, he understood what was happening in Italy. He was a convinced anti-Fascist. The political climate was stifling and so in 1925 he left for America, to work in a coal mine."
The hard-right politician described himself earlier this month as "the Jesus candidate". He is opposed to abortion and openly critical of homosexuality and the teaching of evolution. His website describes him as a "Tea Party kind of guy before there was a Tea Party."
Mrs Santorum, the 83-year-old matriarch of the Italian side of the family, is proud of her relation's achievements but believes his ultra-conservative views are too extreme.
"He could be a great president, but if he really wants to achieve his objective he should soften some of his positions," she added.
Mr Santorum's father, Aldo, died last year. "It's such a shame, he would have felt such joy to see his son launch a bid for the White House," said Mrs Santorum. Cousins, aunts and uncles said Mr Santorum had visited them several times and was particularly taken by Italian cooking and the mountains and forests around Lake Garda.
But there were a few culture clashes between the American and Italian branches of the clan. "Me and my brothers were amazed at the number of ice cubes that he put in his drinks," said a cousin, Michela Santorum. "But he was crazy for Italian food, including polenta."
Mr Santorum was regarded as having just an outside chance in the Republican nomination race until he unexpectedly surged ahead in last week's Iowa caucuses, coming second after losing to Mitt Romney by just eight votes. He was brought back down to earth, however, with a disappointing fifth place finish in Tuesday's New Hampshire primary.
His campaign in South Carolina, the next state to vote in the Republican nomination process, received a boost yesterday when the independent super PAC (Political Action Committee) supporting him reportedly bought more than half a million dollars of new television advertising in the state.
Despite the loss, some of Mr Santorum's relations are getting ready to celebrate, convinced he can win the Republican contest and beat Barack Obama.
Raising a glass of the local merlot, brothers Aldo and Bruno Santorum toasted their American cousin. "To Ricky, and the hope that when he wins he'll send the presidential plane and bring all the Santorums to the White House," Bruno Santorum said. (© Daily Telegraph, London)