Santorum says the JFK 1960 speech delivered while campaigning to be the first Catholic US president, made him feel sick.

Gingrich on the other hand, calls the speech remarkable, telling Fox News that as president he would not obey any foreign religious leader.

Gingrich said Kennedy was declaring "that his first duty as president would be to do the job of president, and I think that's correct."

Where Gingrich and Santorum agree however is they both are of the view that US President Barack Obama is 'anti-religious'.

Santorum's comments have rocked some clergy.

Rev Nick Carter, president of Andover Newton Theological Schools is critical of Santorum's comments saying that Santorum's comments show a misunderstanding of the principle of church and state, that Kennedy laid out.

"The nature of what Kennedy did is he showed that he can be a person of deep personal faith but he can be a political leader who can be trusted by all," Carter said.

Rev. Laura Everett, executive director of the Massachusetts Council of Churches, labelled Santorum's remarks as "hard words to hear."

"When I went back to read [Kennedy's] speech again, I was struck by what a generous and hopeful vision of religious diversity that Kennedy spoke of 50 years ago," Everett said.

Even those who agree with Santorum's sentiments question his turn of phrase. H.L. Champion, president of Baptist.org, said he sympathizes with Santorum's views, but found the comment about throwing up was "superfluous."

On September 12, 1960, Kennedy the democratic candidate for president delivered a speech defending himself from skepticism over his Catholic faith.

Kennedy outlined his vision for America in which no church would impose their will on government, and no president would face a religious test for office.

"I belive in an America where the separation of church and state is absolute," he said.

"I do not speak for my church on public matters and the church does not speak for me."

Sources

• Washington Post
• Boston Globe
• Image: The Blaze

That is the moment, three years ago, that Mr. Gingrich says he decided to become a Roman Catholic, after having been born a Lutheran and joining the Southern Baptist Church in college. In 2009, Mr. Gingrich was baptized in the same Catholic parish church on Capitol Hill where Senator Robert F. Kennedy once attended noonday Mass and sometimes assisted the priest as an altar server.

But Mr. Gingrich represents a new kind of Catholic, one very different from the Kennedys, who were Democrats, political liberals and cradle Catholics shaped by the Irish immigrant church.